MD, Stanford University, Medicine (1999)
PhD, Stanford University, Biophysics (1999)
My research program is primarily centered on the exploration of mechanisms driving hematopoietic disorders in the skin. Compared to hematopoietic disorders (lymphomas, leukemias, and mast cell disease) that involve other organs in the body, such as the lymph node, bone marrow, and spleen, the counterparts of these diseases in the skin have a different clinical presentation, course, and outcome. For example, patients with the most common lymphoma that starts in the skin, mycosis fungoides, can have a long and fruitful life, if the disease is limited to the skin and does not involve other organs in the body. For this reason, clinicians usually treat these patients with more conservative therapies (such as topical steroids) to control the disease, rather than with systemic chemotherapy, as in the case of their systemic counterparts. The most common type of mast cell disease of the skin, urticaria pigmentosa, occurs frequently in children, and can regress before puberty. On the other hand, adult patients with mast cell disease that involve organs other than skin can have a more aggressive clinical course, with a subset of these patients dying from their disease. Although the characteristics of the genes and proteins that cause these diseases are currently being studied, a key discovery would lie in our ability to distinguish patients who are going to do well (because their disease will be limited to the skin) from patients who may not do as well. The importance of this distinction would be in the therapeutic approach: patients with more aggressive disease would get more aggressive therapy. Unfortunately, cutaneous lymphomas are notoriously difficult to diagnose accurately, as they can look very much like reactive processes under the microscope. Similarly, although it is relatively straightforward to render the diagnosis of mast cell disease in the skin, distinguishing mast cell disease that will spontaneously regress from those that will have a more aggressive clinical course can also be challenging.
The aim of my research group is to explore the genetic and protein expression patterns in these diseases when they are limited to the skin, and when they involve organs outside the skin, and to understand the differences between these two scenarios. This may aid greatly in diagnosis if there were, for example, proteins expressed in cutaneous mast cell disorders that were not present in mast cell diseases in other organs. It can also help therapy, if we were able to find specific genetic changes in clinically aggressive mycosis fungoides, which were different from mycosis fungoides limited to the skin. These genetic changes could then be used as a marker for patient response to different kinds of chemotherapeutic drugs. It is possible that drugs could be engineered to specifically interact with modified proteins associated with these genetic changes as well.
The purpose of this study is to learn the effects of an investigational medication, SGN 35, on patients with mycosis fungoides. Despite a wide range of therapeutic options, the treatments are associated with short response duration, thus this condition is largely incurable. This investigational drug may offer less toxicity than standard treatments and have better tumor specific targeting.
Stanford is currently not accepting patients for this trial. For more information, please contact Kokil Bakshi, 650-421-6370.
We will use new technologies to look at the DNA, RNA, proteins, and metabolites in the disease-containing blood, bone marrow, or tissue and normal cells from the skin. Our goal is to analyze all of the genes in the diseased and normal skin sample. By comparing the results of the diseased sample and normal skin cells and the results of the two types of genetic information (DNA and RNA), we should be able to identify genetic changes that are important for the initiation, progression, or treatment response of that particular disorder.
Standard-dose (36-Gy) total skin electron beam therapy (TSEBT) is a highly effective treatment in mycosis fungoides. However, the regimen is time-intensive and may be associated with significant toxicity.We sought to evaluate the efficacy and tolerability associated with low-dose (12-Gy) TSEBT.Data from 3 clinical trials using low-dose (12-Gy) TSEBT were pooled. In all trials, TSEBT-naïve patients with stage IB to IIIA mycosis fungoides were treated with TSEBT (12 Gy, 1 Gy per fraction over 3 weeks). The primary end point was clinical response rate. Secondary end points included time to response and duration of clinical benefit.In all, 33 patients enrolled. Eighteen were male; stages were 22 IB, 2 IIA, 7 IIB, and 2 IIIA. Overall response rate was 88% (29/33), including 9 patients with complete response. Median time to response was 7.6 weeks (3-12.4 weeks). Median duration of clinical benefit was 70.7 weeks (95% confidence interval 41.8-133.8 weeks). Toxicities from TSEBT were mild and reversible.Conclusions are limited because of the small number of patients.Low-dose TSEBT provides reliable and rapid reduction of disease burden in patients with mycosis fungoides, which could be administered safely multiple times during the course of a patient's disease with acceptable toxicity profile.
View details for DOI 10.1016/j.jaad.2014.10.014
View details for PubMedID 25476993
Hematopoietic stem cell transplantation (HCT), formerly known as bone marrow transplantation, is an integral part of treatment for many hematological malignancies. HCT is associated with several complications and comorbidities with differential effects on a wide spectrum of organs and tissues. We present an update on HCT-associated complications such as graft versus host disease (GVHD) and infection, with focus on the surgical pathology of the gastrointestinal (GI) tract, liver, and lung. Although the grading system for GI tract acute GVHD was proposed 40 years ago, recent studies have shed light on minimal histologic criteria for diagnosis of GVHD, as well as its differential diagnosis, including histologic effects of various medications. GI dysfunction in autologous transplant recipients is increasingly appreciated and patients are often biopsied. Acute liver injury in HCT is often due to sinusoidal obstruction syndrome (previously known as venoocclusive disease), or acute GVHD. Liver dysfunction at later time posttransplantation may be associated with acute or chronic GVHD, iron overload, or other causes of hepatitis. Lung injury in HCT is multifactorial, and it remains crucially important to diagnose and treat pulmonary infections. The pulmonary biopsy yields clinically unsuspected diagnoses in the majority of cases and its utilization is likely to increase. The pathology of the skin and kidney in HCT patients are detailed in accompanying articles.
View details for DOI 10.1097/PAP.0000000000000032
View details for PubMedID 25105933
Hematopoietic stem cell transplantation continues to be the mainstay of treatment for many hematologic dyscrasias and malignancies, including acute leukemias, lymphomas, and aplastic anemia. There can be significant complications, however, and often these complications are manifested in the skin as an eruption. Common among these are acute and chronic graft-versus-host disease, erythema multiforme, Stevens-Johnson syndrome/toxic epidermal necrolysis, eruption of lymphocyte recovery, staphylococcal scalded skin syndrome, morbiliform drug eruptions, infections, and toxic erythema of chemotherapy. These entities can show significant clinical and histopathologic overlap, yet accurate distinctions among them are critical to initiating appropriate clinical interventions. In this review, we will discuss the key clinical and histopathologic findings in each entity as well as appropriate differential diagnostic entities.
View details for DOI 10.1097/PAP.0000000000000033
View details for PubMedID 25105934
We report 7 cases of a CD8 lymphoid proliferation of the ear and face with a cytotoxic T-cell phenotype, but an indolent clinical course. All patients presented with stable or slowly growing asymptomatic lesions on the ear, nose, or lower eyelid. Histopathology showed a dense diffuse dermal infiltrate of small- to medium-sized atypical lymphocytes without destructive features. The lymphocytes were positive for CD3, CD8, β-F1, and TIA-1 and negative for CD4, CD30, CD56, granzyme B, and PD-1. Of note, the proliferation index was low in available cases. All patients remained in complete remission at median follow-up of 14 months regardless of treatment modality. Staging was negative for extracutaneous disease in all patients. The clinically indolent behavior and histopathologic phenotype together with a low proliferation index (10%-15%) emphasize the importance of accurate diagnosis and appropriate clinical management to avoid overtreatment and complications of therapy.
View details for DOI 10.1097/DAD.0b013e3182a74c7a
View details for Web of Science ID 000336741500009
Salivary gland choristoma (heterotopic salivary gland tissue) is a rare condition typically seen in the newborn period. This developmental heterotopia is generally nonprogressive, with little risk of malignant transformation. We present the second known reported case of a salivary gland choristoma located on the anterior chest wall. Knowledge of this rare entity will allow for accurate diagnosis and management of this benign anatomic variant.
View details for DOI 10.1111/pde.12159
View details for PubMedID 23679208
IMPORTANCE Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare malignant neoplasm with cutaneous manifestations and a rapidly progressive clinical course. The diagnosis relies on characteristic clinicopathologic and immunopathologic features. However, the overlap of immunophenotypic features with other cancers, as well as newly discovered interpersonal and intrapersonal phenotypic variations, renders the identification of BPDCN challenging. A greater understanding of the proteins expressed by BPDCN might facilitate its recognition and provide insights into its clinical behavior. OBSERVATIONS In 7 of 9 patients at 4 tertiary care institutions, immunohistochemical analysis demonstrated strong CD31/PECAM-1 (platelet endothelial cell adhesion molecule 1) expression by neoplastic cells. Combined with similar findings observed in 1 former patient, 8 of 10 cases of BPDCN were CD31/PECAM-1 positive. CONCLUSIONS AND RELEVANCE Expression of CD31/PECAM-1 by BPDCN adds new information about the antigenic profile of this unusual neoplasm. CD31/PECAM-1 influences multiple cell functions including adhesion, apoptosis, coagulation, host response, and protein synthesis that might affect clinical features of BPDCN such as hemorrhage, aggressive tumor growth, and resistance to therapy. Therefore, the potential role of this molecule in the tumor formation and progression of BPDCN warrants additional exploration.
View details for DOI 10.1001/jamadermatol.2013.7141
View details for PubMedID 24225899
Although in most cases one can easily distinguish between atypical fibroxanthomas and angiosarcomas, hemorrhagic atypical fibroxanthomas can pose a diagnostic problem. In rare cases, the large atypical cells of atypical fibroxanthoma can stain with CD31, leading to the erroneous diagnosis of angiosarcoma. We elected to further study this conundrum with 2 additional markers of lymphatic and vascular elements, namely D2-40 (podoplanin) and Fli-1, respectively. We studied 26 cases of atypical fibroxanthoma and 20 cases of angiosarcoma with Fli-1 and D2-40. We found that both Fli-1 and D2-40 stained a majority of cases of angiosarcoma (16/20 and 12/20, respectively), although only staining a minority of cases of atypical fibroxanthoma (8/26 for both). In addition, D2-40 staining of atypical fibroxanthoma was usually weak when positive, whereas Fli-1 staining of angiosarcomas was mostly strong and nuclear. Thus, both D2-40 and Fli-1 seem to be useful in distinguishing between atypical fibroxanthomas and angiosarcomas.
View details for DOI 10.1097/DAD.0b013e318266b197
View details for Web of Science ID 000317918800008
View details for PubMedID 23518636
The topic of distinguishing atypical fibroxanthoma (AFX) from undifferentiated pleomorphic sarcoma (UPS), formerly malignant fibrous histiocytoma, is highly controversial. Although their clinical behavior is disparate, AFX and UPS commonly appear nearly identical on routine histopathologic examination. Although conceptually useful, subcategorization of UPS into superficial (confined to the dermis and subcutaneous tissue) and deep (involvement of fascia and deeper structures) types has not improved our ability to differentiate UPS from AFX. Numerous authors have purported LN-2 (CD74) immunopositivity as able to distinguish UPS from AFX and to predict those rare AFX likely to behave aggressively, although only a single prior study has been dedicated to evaluating this marker. We performed LN-2 staining of 14 AFX, 8 superficial UPS, and 65 deep UPS specimens using an identical protocol as described by prior authors. Of the 73 total UPS specimens, only 1 (1.4%) stained strongly with LN-2, as compared with 3 of 14 (21%) AFX (P = 0.012). One of 2 (50%) clinically aggressive AFX tumors that later exhibited both local recurrence and metastasis stained strongly for LN-2, whereas 2 of 12 (17%) of the more indolent tumors stained strongly with this marker (P = 0.40). Our data do not replicate prior reports of LN-2 as a sensitive and specific marker for UPS, or as indicative of prognosis for AFX, and therefore does not support the use of LN-2 as either a diagnostic or prognostic marker.
View details for DOI 10.1097/DAD.0b013e318265fb9e
View details for Web of Science ID 000316941200009
The natural history of inherited epidermolysis bullosa (EB) varies significantly across subtypes. When confronted with an infant suspected to have EB, rapidly determining the type and subtype is critical in counselling families accurately about the infant's diagnosis and prognosis. Although transmission electron microscopy (TEM) has been considered the criterion standard for EB diagnosis, immunofluorescence microscopy (IFM) using monoclonal antibodies (mAbs) to EB-specific basement membrane zone proteins has several advantages, but few studies have evaluated the diagnostic utility of IFM. We sought to evaluate the clinical utility of IFM using an expanded panel of EB-specific mAbs. This was a retrospective review of pathology reports from infants younger < 1 year old with suspected EB primarily analyzed with IFM by the Stanford Dermatopathology service. Seventy-seven cases were identified for analysis, of which 20 were suboptimal for IFM analysis. Fifty-five cases were diagnosed with EB and classified as follows: EB simplex (n = 5), junctional EB (n = 31), dystrophic EB (n = 19). TEM was available in 36 of 55 cases (65%). IFM with an expanded panel of EB-specific mAbs should be considered the first-line diagnostic test to evaluate infants with clinically suspected EB.
View details for DOI 10.1111/j.1525-1470.2012.01880.x
View details for Web of Science ID 000315961500009
View details for PubMedID 23461686
Primary cutaneous B-cell lymphomas (PCBCL) are rare. Marginal zone lymphomas and follicle center lymphomas (FCL) represent a majority of these cases, and a significant number of cases present with multiple lesions. It is unclear whether multiple lesions in PCBCL represent dissemination of a single clone or multiple new primary lymphomas. In the current study, we analyzed paired samples from 20 PCBCL patients at more than 1 site (16) or at the same site at different time points (4) and 12 patients with benign lymphoid infiltrates to investigate for the presence or absence of a clone, and if present, whether the clones were identical. Both IGH@ and IGK@ rearrangements were tested using the BIOMED-2 protocol. We identified a clone (IGH@ and/or IGK@) in 19 of 20 (95%) PCBCL patients and 2 of 12 (17%) benign lymphoid infiltrate patients. The B-cell clones were proven to be identical in 11 of 20 (55%) PCBCL patients, including 7 of 16(44%) biopsies from patients with 2 different sites and 4 of 4 biopsies (100%) from patients at the same site but different time points. In 4 cases (3 FCL and 1 marginal zone lymphoma), different clones were detected at different sites, suggesting the possibility of a second simultaneous primary lymphoma. Our results indicate that the presence of identical clones is highly suggestive of lymphoma. To our knowledge, this is the first report to investigate the detection of identical clones in 2 distinct biopsies in PCBCL patients. Although the study is small and the results need to be confirmed in a larger study, these findings suggest that a subset of PCBCL at different sites may represent different primary tumors rather than occurrence of a single disease.
View details for DOI 10.1097/DAD.0b013e318255dbae
View details for Web of Science ID 000314103600006
View details for PubMedID 22588547
To evaluate the efficacy and safety of a novel mechlorethamine hydrochloride, 0.02%, gel in mycosis fungoides. DESIGN Randomized, controlled, observer-blinded, multicenter trial comparing mechlorethamine, 0.02%, gel with mechlorethamine, 0.02%, compounded ointment. Mechlorethamine was applied once daily for up to 12 months. Tumor response and adverse events were assessed every month between months 1 and 6 and every 2 months between months 7 and 12. Serum drug levels were evaluated in a subset of patients.Academic medical or cancer centers.In total, 260 patients with stage IA to IIA mycosis fungoides who had not used topical mechlorethamine within 2 years and were naive to prior use of topical carmustine therapy.Response rates of all the patients based on a primary clinical end point (Composite Assessment of Index Lesion Severity) and secondary clinical end points (Modified Severity-Weighted Assessment Tool and time-to-response analyses).Response rates for mechlorethamine gel vs ointment were 58.5% vs 47.7% by the Composite Assessment of Index Lesion Severity and 46.9% vs 46.2% by the Modified Severity-Weighted Assessment Tool. By the Composite Assessment of Index Lesion Severity, the ratio of gel response rate to ointment response rate was 1.23 (95% CI, 0.97-1.55), which met the prespecified criterion for noninferiority. Time-to-response analyses demonstrated superiority of mechlorethamine gel to ointment (P< .01). No drug-related serious adverse events were seen. Approximately 20.3% of enrolled patients in the gel treatment arm and 17.3% of enrolled patients in the ointment treatment arm withdrew because of drug-related skin irritation. No systemic absorption of the study medication was detected.The use of a novel mechlorethamine, 0.02%, gel in the treatment of patients with mycosis fungoides is effective and safe.clinicaltrials.gov Identifier:NCT00168064.
View details for Web of Science ID 000317668000003
View details for PubMedID 23069814
We reviewed our multicenter experience with gamma-delta (??) T-cell lymphomas first presenting in the skin. Fifty-three subjects with a median age of 61 years (range, 25 to 91 y) were diagnosed with this disorder. The median duration of the skin lesions at presentation was 1.25 years (range, 1 mo to 20 y). The most common presentation was deep plaques (38 cases) often resembling a panniculitis, followed by patches resembling psoriasis or mycosis fungoides (10 cases). These lesions tended to ulcerate overtime (27 cases). Single lesions or localized areas of involvement resembling cellulitis or pyoderma were reported in 8 cases. The most common anatomic site of involvement was the legs (40 cases), followed by the torso (30 cases) and arms (28 cases). Constitutional symptoms were reported in 54% (25/46) of the patients, including some with limited skin involvement. Significant comorbidities included autoimmunity (12 cases), other lymphoproliferative disorders (5 cases), internal carcinomas (4 cases), and viral hepatitis (2 cases). Lymphadenopathy (3/42 cases) and bone marrow involvement (5/28 cases) were uncommon, but serum lactose dehydrogenase (LDH) was elevated in 55% (22/39) of the patients. Abnormal positron emission tomography and/or computed tomography scans in 20/37 subjects mostly highlighted soft tissue or lymph nodes. Disease progression was associated with extensive ulcerated lesions resulting in 27 deaths including complications of hemophagocytic syndrome (4) and cerebral nervous system involvement (3). Median survival time from diagnosis was 31 months. Skin biopsies varied from a pagetoid pattern to purely dermal or panniculitic infiltrates composed of intermediate-sized lymphocytes with tissue evidence of cytotoxicity. The most common immunophenotype was CD3+/CD4+/CD5+/CD8+/BF1+/?-M1+/TIA-1+/granzyme-B+/CD45RA-/CD7-, and 4 cases were Epstein-Barr virus positive. This is the largest study to date of cutaneous ?? T-cell lymphomas and demonstrates a variety of clinical and pathologic presentations with a predictable poor outcome.
View details for DOI 10.1097/PAS.0b013e31826a5038
View details for Web of Science ID 000310059600008
View details for PubMedID 23073324
Sézary syndrome (SS) is an aggressive cutaneous T-cell lymphoma (CTCL) of unknown etiology in which malignant cells circulate in the peripheral blood. To identify viral elements, gene fusions, and gene expression patterns associated with this lymphoma, flow cytometry was used to obtain matched pure populations of malignant Sézary cells (SCs) versus nonmalignant CD4(+) T cells from 3 patients for whole transcriptome, paired-end sequencing with an average depth of 112 million reads per sample. Pathway analysis of differentially expressed genes identified mis-regulation of PI3K/Akt, TGF?, and NF-?B pathways as well as T-cell receptor signaling. Bioinformatic analysis did not detect either nonhuman transcripts to support a viral etiology of SS or recurrently expressed gene fusions, but it did identify 21 SC-associated annotated long noncoding RNAs (lncRNAs). Transcriptome assembly by multiple algorithms identified 13 differentially expressed unannotated transcripts termed Sézary cell-associated transcripts (SeCATs) that include 12 predicted lncRNAs and a novel transcript with coding potential. High-throughput sequencing targeting the 3' end of polyadenylated transcripts in archived tumors from 24 additional patients with tumor-stage CTCL confirmed the differential expression of SC-associated lncRNAs and SeCATs in CTCL. Our findings characterize the SS transcriptome and support recent reports that implicate lncRNA dysregulation in human malignancies.
View details for DOI 10.1182/blood-2012-04-423061
View details for Web of Science ID 000311619200020
View details for PubMedID 22936659
We investigated the role of adhesion molecules in skin involvement by acute myeloid leukemia (AML) using immunohistochemical analysis. Ten paired cases of skin and bone marrow biopsy specimens from patients with myeloid leukemia cutis (MLC) and 15 bone marrow biopsy specimens from patients without MLC were studied with antibodies directed against CD29, CD34, CD54, CD62-L, CD183, and cutaneous lymphocyte antigen (CLA). CLA was expressed in all cases of leukemia whereas CD54 was negative within blasts. CD62-L was expressed in 4 of 10 specimens of marrow infiltrates with MLC and 6 of 10 specimens of matching skin infiltrates; in marrows without MLC, only 2 of 15 were positive. CD29 was expressed in 1 of 10 marrow infiltrate specimens with MLC and 4 of 10 matching skin infiltrate specimens; in marrows without MLC, only 1 of 15 were positive. CD183 was expressed in 1 of 10 marrow infiltrate specimens with MLC and 4 of 10 matching skin infiltrate specimens; in marrows without MLC, CD183 was negative. The gain of CD62-L, CD29, and CD183 expression in bone marrow and skin infiltrates in leukemia cutis, relative to bone marrow infiltrates of cases without MLC, suggests a role for these markers in AML homing to skin.
View details for DOI 10.1309/AJCP34YERPZSCYKQ
View details for Web of Science ID 000306536000017
View details for PubMedID 22904142
Myeloid leukemia cutis (LC) and blastic plasmacytoid dendritic cell neoplasm (BPDCN) are morphologically indistinguishable malignancies that frequently manifest in the skin. Separating myeloperoxidase-negative LC from BPDCN may be particularly challenging. We identified a panel of immunohistochemical stains to distinguish myeloid LC (23 cases) from BPDCN (12 cases): myeloperoxidase, which stained 7 cases (30%) of LC and 0 cases (0%) of BPDCN; CD56, which stained 12 cases (52%) of LC and all 12 cases (100%) of BPDCN; CD4, which stained 2 cases (9%) of LC and all 12 cases (100%) of BPDCN; CD123, which stained 4 cases (17%) of LC and 10 cases (83%) of BPDCN; and Tcl-1, which stained 2 cases (9%) of LC and 9 (82%) of 11 cases of BPDCN. It is interesting that CD33 was not helpful; it stained 18 (78%) cases of LC and 11 cases (92%) of BPDCN. Our results indicate that a panel that includes CD4, CD56, CD123, and Tcl-1 can appropriately distinguish between these 2 entities.
View details for DOI 10.1309/AJCP9IS9KFSVWKGH
View details for Web of Science ID 000301081000005
View details for PubMedID 22338048
We describe a case of multiple, discrete, hypopigmented macules in the suprapubic and axillary region in a healthy 3-year-old girl. The lesions first appeared at approximately 9 months of age and increased in number over time. Initial histopathologic examination by an outside dermatopathologist at 1 year of age was reported as showing nonspecific histologic changes. A repeat biopsy at 3 years of age showed large intraepidermal clear cells that expressed CKAE1/CAM5.2, CK7, and BRST2. These findings are diagnostic for clear-cell papulosis, a rare condition that primarily affects children. Without great clinical and pathologic suspicion, this is a diagnosis that can often be overlooked because the histologic findings are virtually identical to those of normal skin.
View details for DOI 10.1111/j.1525-1470.2011.01614.x
View details for Web of Science ID 000301434800012
View details for PubMedID 22142549
The morphologic distinction between cutaneous marginal zone lymphoma (CMZL) and secondary cutaneous involvement by B-cell chronic lymphocytic leukemia (B-CLL) can be difficult. Both entities can show very similar architectural patterns of involvement in the skin and not uncommonly, the skin can be the first site of presentation of B-CLL in the elderly. We reviewed biopsies of 13 patients with cutaneous B-CLL and 14 patients with CMZL to compare their histologic and immunohistochemical features. CMZL and cutaneous B-CLL both predominantly exhibited a nodular pattern of skin involvement (9 of 13 B-CLL, 9 of 14 CMZL) with a minority of cases demonstrating a diffuse pattern (4 of 13 B-CLL, 4 of 14 CMZL). Although reactive germinal centers (12 of 14 cases) and plasma cells (10 of 14 cases) were seen more often in CMZL, plasma cells were also observed in cases of B-CLL (4 of 13). The lesional cells of B-CLL expressed CD79, CD5, CD23, and CD43, although CMZL did not express CD5 or CD43. Although we noted light chain restriction in 13 of 14 cases of CMZL cases, we also observed light chain restriction in 4 of 13 cases of B-CLL. Our results indicate that CMZL and B-CLL can be morphologically similar and both may show light chain restriction. Complete immunophenotyping is necessary to ensure that all cases are correctly classified.
View details for DOI 10.1097/DAD.0b013e31821528bc
View details for Web of Science ID 000299325900005
View details for PubMedID 22257836
A granulomatous infiltrate in association with cutaneous T-cell lymphoma is uncommon. The diagnosis of mycosis fungoides can be difficult in the setting of an exuberant granulomatous infiltrate that obscures the neoplastic lymphoid infiltrate, thereby mimicking a granulomatous dermatitis. Therefore, the clinical context and supplemental molecular analysis, such as the demonstration of a monoclonal T-cell population, may assist in diagnosis. Monoclonal T-cell populations have been reported in association with inflammatory conditions and serve as a diagnostic pitfall. The frequency of T-cell clonality in association with granulomatous dermatitides has not yet been established.We identified 29 patients with granulomatous dermatitis who had biopsies at two distinct body sites. Results were correlated with clinical follow up and with clonal T-cell receptor-gamma chain rearrangement as detected by polymerase chain reaction-based analysis (dual TCR-PCR).Clinical follow up was obtained in 17 of 29 cases (58.6%). Twenty-five of 29 cases of granulomatous dermatitis lacked T-cell monoclonality. Three cases of granuloma annulare contained a T-cell clone in one of the two biopsies. One case of necrobiotic xanthogranuloma showed an identical T-cell clone in multiple biopsies.The use of dual TCR-PCR analysis, that is, T-cell clonality analysis in biopsy specimens from two different sites, serves as an adjunct to assist in distinguishing granulomatous inflammatory reactions from granulomatous T-cell lymphoma, including granulomatous mycosis fungoides. The occasional finding of a T-cell clone in a granulomatous dermatitis underscores the importance of clinicopathological correlation in daily diagnosis.
View details for DOI 10.1111/j.1600-0560.2011.01727.x
View details for Web of Science ID 000293177000005
View details for PubMedID 21645036
Sebaceous carcinoma is an uncommon and potentially aggressive malignancy that exhibits sebaceous differentiation. Approximately 75% of cases arise in the periocular region. Sebaceous carcinoma is rare in the pediatric population and its presentation in this age group is not well documented in the dermatopathology literature. We report the case of a 15-year-old male with sebaceous carcinoma who was first seen with a nodular lesion involving the skin of the left orbit/temporal area. A shave biopsy was performed which showed an infiltrative proliferation of basaloid cells that focally exhibited sebaceous differentiation, including the formation of incipient sebocytes. Immunohistochemically, the tumor cells expressed epithelial membrane antigen (EMA) and CK5/6, while a lack of Ber-EP4 was observed. Based upon these attributes, the diagnosis of sebaceous carcinoma was rendered. Subsequent immunohistochemical analysis for a possible DNA mismatch repair enzyme defect revealed that all four mismatch repair gene products showed retained expression, thereby providing no support for the presence of underlying Muir-Torre syndrome. Sebaceous carcinomas are exceptional in the pediatric age group and are rarely documented in the dermatopathology literature. Knowledge that this adult carcinoma can occur mostly in the pediatric age group may aid in the recognition of this uncommon malignancy.
View details for DOI 10.1111/j.1600-0560.2010.01662.x
View details for Web of Science ID 000288867300010
View details for PubMedID 21251036
Topically applied calcineurin inhibitors have been shown to be effective in the treatment of atopic dermatitis. When systemically administered, these agents cause immunosuppression via inhibition of calcineurin in lymphocytes. As topical agents, the mechanism of action is poorly defined.To test the hypothesis that skin-infiltrating lymphocytes are directly targeted when calcineurin inhibitors are applied to the skin.Ten patients with atopic dermatitis were treated with 1% pimecrolimus cream twice daily to target lesions. Skin biopsies were performed before and 48 h after beginning therapy. We assessed the cellular localization of NFAT1 and NFAT2 as a surrogate measure of intracellular calcineurin activity (e.g. increasing cytoplasmic localization with increasing calcineurin inhibition).All patients showed a clinical response, at both 48 h and 2 weeks. As previously described, NFAT2 localized to the follicular keratinocytes, and its activation was partially inhibited by topical pimecrolimus. NFAT1 was found to be expressed by follicular and interfollicular keratinocytes, and its mostly nuclear localization was not affected by topical pimecrolimus therapy. Both NFAT1 and NFAT2 were found in the infiltrating lymphocytes. However, using both manual counting as well as an automated method to assess nuclear intensity of NFAT staining, we found that the proportion of infiltrating leucocytes with nuclear ('activated') NFAT did not change following therapy with pimecrolimus.Our results suggest that topical pimecrolimus does not act primarily by inhibiting the calcineurin/NFAT axis in lymphocytes but may instead act by other mechanisms, possibly by decreasing NFAT2 activity in follicular keratinocytes.
View details for DOI 10.1111/j.1365-2133.2010.10190.x
View details for Web of Science ID 000289898200012
View details for PubMedID 21166661
CD163, a hemoglobin scavenger receptor, is expressed in monocytes and macrophages. Recent work has shown that this marker is specific for neoplasms of histiocytic differentiation. Our aim was to test the ability of CD163 to separate cutaneous histiocytomas from their morphologic mimics. We tested the expression of CD163 in 78 cases, including 19 xanthogranulomas, 16 atypical fibroxanthomas, 6 reticulohistiocytomas, 8 epithelioid cell histiocytomas, 9 cases of Langerhans cell histiocytosis, 10 xanthomas, and 10 intradermal Spitz nevi. CD163 expression was seen in all xanthogranulomas and reticulohistiocytomas, 4 epithelioid cell histiocytomas, 2 cases of Langerhans cell histiocytosis, and 8 xanthomas but was absent in atypical fibroxanthomas and Spitz nevi. CD163 is an excellent marker for confirming histiocytic differentiation and is useful in eliminating morphologic mimics such as Spitz nevi from the differential diagnosis. The lack of CD163 in atypical fibroxanthomas argues against a histiocytic origin for this tumor.
View details for DOI 10.1309/AJCP88IRBPXQZYIR
View details for Web of Science ID 000277846700013
View details for PubMedID 20472850
The distinction between mycosis fungoides (MF) and inflammatory dermatoses (ID) by clinicopathologic criteria can be challenging. There is limited information regarding the performance characteristics and utility of TCRG and TCRB clonality assays in diagnosis of MF and ID from paraffin-embedded tissue sections. In this study, PCR tests were performed with both TCRG and TCRB BIOMED-2 clonality methods followed by capillary electrophoresis and Genescan analysis using DNA samples from 35 MF and 96 ID patients with 69 and 133 paraffin-embedded specimens, respectively. Performance characteristics were determined for each test individually and in combination. TCRG and TCRB tests demonstrated identical sensitivity (64%) and specificity (84%) when analyzed as individual assays. The positive predictive value, negative predictive value, and change of posttest MF probability over a range of MF pretest probabilities were obtained. These data were used to construct an algorithm for sequential use of TCRG and TCRB. As single tests, commercially available BIOMED-2 PCR-based TCRG and TCRB clonality tests on paraffin-embedded tissue have no significant difference in terms of sensitivity and specificity. Combined use of the two tests in patients with intermediate pretest probabilities as proposed in the algorithm could improve test utility.
View details for DOI 10.2353/jmoldx.2010.090123
View details for Web of Science ID 000277531700009
View details for PubMedID 20203005
The diagnosis of myeloid leukemia cutis can be difficult, particularly in the context of an initial skin biopsy with a malignant hematopoietic neoplasm. We studied the immunohistochemical characteristics of 33 cases of myeloid leukemia cutis diagnosed at Stanford University Medical Center, Stanford, CA, 1996-2007, and compared them with the corresponding bone marrow blast immunophenotype and World Health Organization classification (2008). In the skin, CD43 marked 97% of cases (32/33), myeloperoxidase marked 42% (14/33), CD68 marked 94% (31/33), CD163 marked 25% (7/28), and CD56 marked 47% (14/30). CD34 and CD117 were predominantly negative. In 19 cases in which myeloperoxidase was negative, all marked with CD68 and CD43. The flow cytometric immunophenotype of the leukemic blasts in the bone marrow was discordant with the immunohistochemical profile in the skin in all cases, showing loss or gain of at least 1 antigen. Given the immunophenotypic differences between skin and bone marrow blasts, we provide an updated immunohistochemical approach to the diagnosis of myeloid leukemia cutis.
View details for DOI 10.1309/AJCP6GR8BDEXPKHR
View details for Web of Science ID 000267206400014
View details for PubMedID 19864240
View details for PubMedID 19606077
Although the new World Health Organization-European Organization for Research and Treatment of Cancer classification focuses on providing uniformity in the diagnosis of cutaneous lymphomas, cutaneous peripheral T-cell lymphoma (PTL) remains a poorly defined subgroup. As follow-up to a study of systemic PTL complicated by a proliferation of B cells, we studied 16 cases of cutaneous PTL that contained morphologically atypical T cells associated with a significant infiltrate of B cells (about 20%-50%). A clonal T-cell receptor gamma chain gene rearrangement was present in all cases. In contrast, a clonal immunoglobulin heavy chain gene rearrangement was present in only 1 case. Clinical staging in 14 cases identified systemic involvement in 2. At last follow-up, both patients with systemic involvement had died of disease, and the majority of patients with primary cutaneous disease were alive (11/12). The presence of numerous atypical B cells and T cells caused diagnostic confusion in these cases. Comprehensive pathologic studies, coupled with clinical staging, are necessary for the accurate diagnosis of this unusual manifestation of cutaneous PTL.
View details for DOI 10.1309/AJCP5W0VOCSVOBRA
View details for Web of Science ID 000266238600010
View details for PubMedID 19461087
Studies suggest that primary extranodal follicular lymphoma (FL) is not infrequent but it remains poorly characterized with variable histologic, molecular, and clinical outcome findings. We compared 27 extranodal FL to 44 nodal FL using morphologic, immunohistochemical, and molecular genetic techniques and evaluated the clinical outcome of these 2 similarly staged groups. Eight cases of primary cutaneous follicle center lymphoma were also studied. In comparison to nodal FL, a greater number of extranodal FL contained a diffuse growth pattern (P=0.004) and lacked CD10 expression (P=0.014). Fifty-four percent of extranodal and 42% of nodal FL cases showed evidence of t(14;18), with minor breakpoints (icr, 3'BCL2, 5'mcr) more commonly found in extranodal cases (P=0.003). Outcome data showed no significant differences in overall survival (P=0.565) and progression-free survival (P=0.627) among extranodal, nodal, and primary cutaneous follicle center lymphoma cases. Analysis of all cases by t(14;18) status indicate that the translocation-negative group is characterized by a diffuse growth pattern (P=0.043) and lower BCL2 expression (P=0.018). The t(14;18)-positive group showed significantly better overall survival (P=0.019) and disease-specific survival (P=0.006) in comparison with the t(14;18)-negative group. In low stage FL, the status of t(14;18) seems to be more predictive of outcome than origin from an extranodal versus nodal site.
View details for Web of Science ID 000264818800014
View details for PubMedID 19065102
We report an unusual primary cutaneous neuroendocrine carcinoma that shows histologic and immunohistochemical features of ganglioneuroblastoma/differentiating neuroblastoma. The neoplasm is composed predominantly of small atypical neoplastic cells embedded in distinct clusters of immature and mature ganglion cells with associated neuropil. The neoplastic cells show strong perinuclear staining for cytokeratin 20 (CK20) with a dot-like pattern, supporting our contention that this is an unusual variant of Merkel cell carcinoma. To the best of our knowledge, ganglioneuroblastoma-like differentiation has not been previously described in Merkel cell carcinoma.
View details for Web of Science ID 000264558100015
View details for PubMedID 19318809
Pigmented dermatofibrosarcoma protuberans (DFSP; Bednar tumor) constitutes 5%-10% of all cases of DFSP and shows morphologic features that overlap with melanocytic and fibrous proliferations. We report 2 unusual cases of pigmented fibrous proliferations that demonstrate features of dermatofibromas and DFSP. The first case is that of a 19-year-old man with a 3-year history of a slowly growing pigmented lesion on the right arm. On clinical exam, the lesion was a 7-mm firm pigmented papulonodular lesion. The second case is that of a 31-year-old woman with a 4- to 5-year history of a slowly enlarging, asymptomatic "dark area" on the right buttock. On clinical exam, the lesion was a 2-cm darkly pigmented flat nodule. Morphologically, both lesions are primarily dermal proliferations of spindled cells admixed with pigmented dendritic melanocytes. The lesional cells trap collagen fibers at the periphery and there is basal cell hyperpigmentation. Adnexal structures are effaced, but significant trapping of subcutaneous fat is not present. By immunohistochemistry, both lesions show focal CD34 positivity but are negative for Factor XIIIa and melanocytic markers. Although overlap between standard dermatofibromas and DFSP is well documented in the literature, pigmented fibrous lesions with features of both entities are not well described.
View details for Web of Science ID 000259325000015
View details for PubMedID 18806495
Primary cutaneous B-cell lymphomas (CBCL) are a diverse group of lymphomas that are limited to the skin at the time of diagnosis. Recently, standardized polymerase chain reaction protocols for immunoglobulin (Ig) rearrangement in nodal malignancies using the BIOMED-2 method have been studied extensively. However, reports of investigations of Ig clonality in CBCL using the BIOMED-2 method have been scant. We hypothesized that clonality detection in CBCL with the BIOMED-2 method could effectively distinguish malignant from benign B-cell-rich infiltrates in the skin. Formalin-fixed tissue samples from 26 patients with CBCL and 23 with benign lymphoid infiltrates were analyzed for Ig clonality using standardized BIOMED-2 polymerase chain reaction protocols. The (14;18) translocation was also assessed. A clone was detected in 22 (85%) of the 26 patients with CBCL [12/15 (80%) marginal zone B-cell lymphoma; 10/11 (91%) follicle center lymphoma] and in 1 (4%) of the 23 patients with benign infiltrates. The (14;18) translocation was present in 3 (12%) of the 26 patients with CBCL [1/15 (7%) marginal zone B-cell lymphoma; 2/11 (18%) follicle center lymphoma]. Our preliminary data indicate that Ig clonality can be detected in formalin-fixed samples of CBCL with meaningful sensitivity (85%) and high specificity (96%) using the BIOMED-2 method. This study forms the basis for further investigating the role of Ig clonality in distinguishing CBCL from benign lymphoid infiltrates that may pose a challenge in morphologic diagnosis.
View details for Web of Science ID 000259325000002
View details for PubMedID 18806482
The classification of primary cutaneous large B-cell lymphoma (PCLBCL) is based on standard morphology, immunohistochemistry, and clinical presentation. There are two major subtypes in the current WHO-EORTC classification: follicle center lymphoma and diffuse large B-cell lymphoma, leg-type (DLBCL-LT). The goals of this study were to examine a series of DLBCLs to determine (1) whether the immunohistochemical paradigm of germinal center B-cell and non-germinal center B-cell types of systemic DLBCL could be applied to PCLBCL; (2) whether application of the newly described germinal center B-cell marker, human germinal center-associated lymphoma (HGAL) also discriminates between these types as a further support for germinal center B-cell origin for primary cutaneous center lymphoma; and (3) whether any of these biologic markers were of prognostic significance. To this end, 32 cases of diffuse PCLBCL (22 primary cutaneous follicular center lymphomas and 10 DLBCL-LT) were classified based on the WHO-EORTC criteria and studied for expression of CD20, BCL2, BCL6, CD10, MUM-1, and HGAL by immunohistochemistry. Results were correlated with clinical features. HGAL and BCL6 expression and germinal center B-cell phenotype were associated with primary cutaneous follicular center lymphoma. The combination of HGAL and BCL6 positivity had the highest sensitivity (88%) and specificity (100%) for predicting subtype compared to either marker alone. Both HGAL and BCL6 were associated with the germinal center B-cell phenotype. The correlation of HGAL expression with the germinal center B-cell phenotype demonstrates the role of this marker in the classification of cutaneous large B-cell lymphomas. BCL6 expression was the only immunohistochemical marker associated with overall survival. Characterizing PCLBCLs with markers of B-cell maturation stage is a useful framework for studying, classifying, and clinically stratifying these lymphomas.
View details for DOI 10.1038/modpathol.2008.30
View details for Web of Science ID 000256112900002
View details for PubMedID 18264083
Hydroa-like lymphoma is an extremely rare and aggressive lymphoma described in children from Latin American countries (Mexico, Guatemala and Peru) and Asia (Japan, Korea and Taiwan). Clinically, patients present with vesicles, ulcers and scars occurring on both sun-exposed and non-sun-exposed areas. In contrast to classical hydroa vacciniforme, hydroa-like lymphoma is associated with systemic lymphoma of T-cell type that expresses either CD4 or CD8. We report the findings from two unusual cases of hydroa-like lymphoma that, unlike the cases described thus far in the literature, express CD56 and resemble natural killer cell lymphomas. Two 9-year-old boys presented with clinical histories of waxing and waning ulcerative blistering lesions since 3 years of age. Histological examination of skin biopsies from both cases showed periappendigeal infiltrates of atypical lymphocytes. Immunohistochemical studies showed that the cells were highlighted by markers for CD3, CD56 and CD30, but did not express CD4 and CD8. Both patients were alive with disease 1 year later. Hydroa-like lymphoma with natural killer-cell phenotype may have a similar outcome to T-cell derived hydroa-like lymphoma, but the prognosis appears to be better than classic NK lymphomas, which in general behave in an aggressive fashion.
View details for DOI 10.1111/j.1600-0560.2007.00836.x
View details for Web of Science ID 000254808200010
View details for PubMedID 17976208
Merkel cell carcinoma is a rare and aggressive form of skin cancer of neuroendocrine origin. Its treatment involves wide excision and radiotherapy but no effective therapy exists for advanced disease. Upregulation of the platelet-derived growth factor receptor family of tyrosine kinases, PDGFRA and KIT, has a crucial role in cancer development. Several studies have shown expression of the tyrosine kinase receptor KIT (CD117) in Merkel cell carcinoma. In this study, we examined the expression and mutational status of KIT and PDGFRA in 14 primary and 18 metastatic Merkel cell carcinoma. The expression of KIT and PDGFRA and their respective ligands, stem cell factor (SCF) and PDGFA, was assessed by immunohistochemistry. In addition, we analyzed KIT exons 9, 11, 13 and 17, and PDGFRA exons 10, 12 and 18 for the presence of activating mutations. We found that only 53% of cases of Merkel cell carcinoma expressed KIT, which was mostly seen as diffuse weak staining, and SCF expression was observed only in 31% of cases. In contrast, 87 and 81% of cases expressed PDGFRA and PDGFA, respectively. We observed coexpression of SCF and KIT in only 5 of 32 cases (16%) whereas 25 of 31 cases (81%) showed coexpression of PDGFRA and its ligand PDGFA. While we documented silent mutations in exon 17 of KIT and exons 10, 12 and 18 of PDGFRA, we were not able to identify any known activating mutations. Our results indicate that there is no correlation between positive immunostaining and occurrence of activating mutations in KIT and PDGFRA. Moreover, the presence of KIT/SCF and PDGFRA/PDGFA coexpression in a proportion of cases may indicate an autocrine/paracrine stimulation loop. We think therefore that imatinib mesylate is less likely to be an effective therapy for Merkel cell carcinoma, unless activating mutations exist in other exons of these receptor kinases.
View details for DOI 10.1038/modpathol.3800980
View details for Web of Science ID 000252662900004
View details for PubMedID 18084259
Cutaneous mast cell disorders are uncommon, but a subset, especially mastocytoma and mast cell leukemia, can histologically mimic myeloid leukemia cutis. Our objective was to employ a panel of cytochemical and immunohistochemical markers to determine which ones would be most useful in separating these two entities.We stained 17 cases of cutaneous mast cell disease and 20 cases of myeloid leukemia cutis with Giemsa, toluidine blue, or pinacyanol erythrosinate (PE), as well as with antibodies against mast cell tryptase, microphthalmia transcription factor (MiTF), CD117 (c-kit), myeloperoxidase, CD43, CD25, CD2, and CD68.Mast cell tryptase and MiTF emerged as highly sensitive and specific markers for mast cell disease in this context, as both antibodies stained all cases of mast cell diseases but none of myeloid leukemia cutis. Although CD117 stained all cases of mast cell disease, it also stained 2 of 18 cases of myeloid leukemia cutis. PE appeared to be specific for mast cell disease, as 11 of 12 cases stained with this marker, compared with 0 of 18 cases of myeloid leukemia cutis.Our results show that mast cell tryptase and MiTF are equally effective in distinguishing mast cell disease from myeloid leukemia cutis.
View details for DOI 10.1111/j.1600-0560.2006.00602.x
View details for Web of Science ID 000245099700001
View details for PubMedID 17381798
NKI/C3 originally was described as a marker for melanoma. Recently, it resurfaced as a marker to separate cellular neurothekeoma from other dermal tumors in the differential diagnosis. To determine the sensitivity and specificity of NKI/C3, we evaluated its staining pattern in 709 normal and neoplastic tissues, including 92 dermal tumors, using tissue microarrays and conventional sections. We found that although NKI/C3 is positive in only a few normal tissues, it stains a broad spectrum of neoplastic tissues. NKI/C3 is also positive in many dermal tumors of possible histiocytic origin, including juvenile xanthogranuloma (6/10), atypical fibroxanthoma (4/12), cellular fibrous histiocytoma (5/10), reticulohistiocytoma (3/6), and xanthoma (8/10). However, it is negative in epithelioid cell histiocytomas (0/7) and Langerhans cell histiocytosis (0/9). Given the wide spectrum of positive staining in morphologic mimics of cellular neurothekeomas, pathologists should be cautious when making this diagnosis based solely on positive staining with NKI/C3.
View details for DOI 10.1309/3J3B7XVQF6CM0KTB
View details for Web of Science ID 000240638900008
View details for PubMedID 16938667
Vascular endothelial growth factor (VEGF) exerts crucial functions during pathological angiogenesis and normal physiology. We observed increased hematocrit (60-75%) after high-grade inhibition of VEGF by diverse methods, including adenoviral expression of soluble VEGF receptor (VEGFR) ectodomains, recombinant VEGF Trap protein and the VEGFR2-selective antibody DC101. Increased production of red blood cells (erythrocytosis) occurred in both mouse and primate models, and was associated with near-complete neutralization of VEGF corneal micropocket angiogenesis. High-grade inhibition of VEGF induced hepatic synthesis of erythropoietin (Epo, encoded by Epo) >40-fold through a HIF-1alpha-independent mechanism, in parallel with suppression of renal Epo mRNA. Studies using hepatocyte-specific deletion of the Vegfa gene and hepatocyte-endothelial cell cocultures indicated that blockade of VEGF induced hepatic Epo by interfering with homeostatic VEGFR2-dependent paracrine signaling involving interactions between hepatocytes and endothelial cells. These data indicate that VEGF is a previously unsuspected negative regulator of hepatic Epo synthesis and erythropoiesis and suggest that levels of Epo and erythrocytosis could represent noninvasive surrogate markers for stringent blockade of VEGF in vivo.
View details for DOI 10.1038/nm1428
View details for Web of Science ID 000238862800066
View details for PubMedID 16799557
Distinction between cellular fibrous histiocytomas (FHs) with a deep component and dermatofibrosarcoma protuberans (DFSPs) can pose diagnostic problems. While CD68, CD34, and Factor XIIIa are helpful in distinguishing between these entities, none are diagnostically absolute. Recent work with CD163, a hemoglobin scavenger receptor, has demonstrated that this marker has high specificity for monocytes, macrophages, and histiocytes. Our goal is to evaluate the utility of CD163 in the diagnosis of dermatofibromas (DFs), cellular FHs, and DFSPs.Sixty cases including 19 DFs, 23 cellular FHs with a deep component, and 18 DFSPs were tested with antibodies against CD163, CD68, CD34, and Factor XIIIa.CD163 was expressed in 17/19 (89%) DFs, 23/23 (100%) cellular FHs, and 3/18 (17%) DFSPs. CD68 was positive in 8/19 (42%) DFs, 19/23 (83%) cellular FHs, and 1/16 (6%) DFSPs. CD34 was expressed in 1/19 (5%) DFs, 5/23 (22%) cellular FHs, and 100% of DFSPs. Factor XIIIa labeled 4/19 (21%) DFs, 11/23 (48%) cellular FHs, and 0/17 cases of DFSPs.CD163 expression is helpful in distinguishing between cellular FHs and DFSPs and will be useful in a panel of antibodies when these entities are in the differential diagnosis. Sachdev R, Sundram U. Expression of CD163 in dermatofibroma, cellular fibrous histiocytoma, and dermatofibrosarcoma protuberans: comparison with CD68, CD34, and Factor XIIIa.
View details for Web of Science ID 000237095400004
View details for PubMedID 16640542
Cutaneous manifestations of acute promyelocytic leukemia are rare but well documented. Skin biopsies of leukemia can be difficult to confirm using morphology alone, and paraffin section immunophenotyping is not specific in separating acute promyelocytic leukemia from other acute myeloid leukemias involving the skin or inflammatory conditions, such as Sweet's syndrome and all-trans retinoic acid-associated genital ulcers, which may mimic leukemia cutis. Fluorescence in situ hybridization has been shown to be a fast and effective method of detecting the PML/RARA fusion gene characteristic of acute promyelocytic leukemia in fresh blood and bone marrow samples. Fluorescence in situ hybridization has also been demonstrated to be effective in detecting other chromosomal rearrangements in paraffin-embedded tissue. This retrospective study of cutaneous lesions from four patients with acute promyelocytic leukemia evaluates the utility of performing fluorescence in situ hybridization to confirm the presence of cutaneous manifestations of acute promyelocytic leukemia in formalin-fixed, paraffin-embedded skin biopsies. All patients had previous bone marrow findings of acute promyelocytic leukemia with characteristic morphology, immunophenotype, and cytogenetic studies, which detailed the presence of the t(15;17)(q22;q12) rearrangement. Two skin biopsies showed an infiltrate of blastic cells involving the dermis in a diffuse pattern and one biopsy had a perivascular/periadnexal pattern. The fourth case, involving the scrotum, showed a predominant neutrophilic infiltrate diffusely involving the dermis and epidermis with a subset of blastic cells. Nuclei were extracted from core biopsies of the formalin-fixed paraffin-embedded tissue and fluorescence in situ hybridization was performed using a dual color, dual fusion PML / RARA probe. All cases showed evidence of the t(15;17) rearrangement, with 90, 79, 51 and 16% positive signal patterns, each well above background limits. Fluorescence in situ hybridization appears to be a robust technique to detect cutaneous manifestations of acute promyelocytic leukemia in formalin-fixed paraffin-embedded skin biopsies.
View details for DOI 10.1038/modpathol.3800465
View details for Web of Science ID 000233372100006
View details for PubMedID 16056248
Systemic B-cell lymphomas have been studied using microarrays, which has led to a better understanding of their molecular characteristics. Initial microarray studies of these lymphomas have implicated several genes as important predictors of outcome. In this study, we used a tissue microarray (TMA) to characterize primary cutaneous large B-cell lymphomas (PCLBCL).We studied 14 patients for whom clinical follow up was available, including four patients whose lesions were limited to the leg on presentation. Immunohistochemical staining with CD20, CD44, CD21, CD5, CD10, bcl-2, bcl-6, Ki67, p53, and multiple myeloma 1 (MUM1) was examined.Our results identify two subgroups of lymphomas. The first group showed staining with bcl-6 and had an overall survival of 176 months (p = 0.003). The majority of this group was negative for MUM1. The second group lacked staining with bcl-6 and had an overall survival of 26 months, with a majority of these cases staining with MUM1. Three of four patients with PCLBCL of the leg showed no staining with bcl-6.Our study demonstrates the utility of TMAs in the analysis of PCLBCL and that expression of bcl-6 and MUM1 correlates with survival.
View details for Web of Science ID 000226857100005
View details for PubMedID 15701085
Soluble receptors to vascular endothelial growth factor (VEGF) can inhibit its angiogenic effect. Since angiogenesis is involved in wound repair, we hypothesized that adenovirus-mediated gene transfer of a soluble form of VEGF receptor 2 (Flk-1) would attenuate wound healing in mice. C57Bl/6J and genetically diabetic (db/db) mice (each n=20) received intravenous (i.v.) injections of recombinant adenoviruses (10(9) PFU) encoding the ligand-binding ectodomain of VEGF receptor 2 (Flk-1) or cDNA encoding the murine IgG2alpha Fc fragment (each n=10). At 4 days after gene transfer, two full-thickness skin wounds (0.8 cm) were created on the dorsum of each animal. Wound closure was measured over 9-14 days after which wounds were resected for histological analysis. Prior to killing, fluorescent microspheres were systemically injected for quantitation of wound vascularity. Single i.v. injections of adenoviruses encoding soluble Flk-1 significantly decreased wound angiogenesis in both wild-type and diabetic mice. Fluorescence microscopy revealed a 2.0-fold (wild type) and 2.9-fold (diabetic) reduction in wound vascularity in Flk-1-treated animals (p<0.05). Impairment of angiogenesis was confirmed by CD31 immunohistochemistry. Interestingly, despite significant reductions in wound vascularity, wound closure was not grossly delayed. Our data indicates that while VEGF function is essential for optimal wound angiogenesis, it is not required for wound closure.
View details for DOI 10.1038/sj.gt.3302162
View details for Web of Science ID 000188329600011
View details for PubMedID 14737090
The diagnosis of malignant melanoma remains one of the most difficult to render in surgical pathology, partially because of its extreme histologic variability. Limits in the sensitivity and/or specificity of the currently available melanocytic markers such as anti-S100, HMB45, and anti-MelanA further complicate this problem. Previous work has demonstrated that the B-cell proliferation/differentiation marker MUM1/IRF4 is detected in malignant melanoma and hematolymphoid malignancies, but not in any other neoplasm tested (including colonic, lung, breast, and ovarian carcinomas). In the current study, we have examined MUM1 protein expression in 61 melanocytic lesions and compared the diagnostic usefulness of this marker with that of anti-S100, HMB45, and anti-MelanA. The results indicate that MUM1 is positive in 33/36 (92%) cases of melanoma (21/22 [95%] conventional primary melanomas and 12/14 [86%] metastatic melanomas). In comparison, positivity was seen with anti-S100 in 36/36 cases (100%, 22 primary and 14 metastatic), HMB45 in 28 cases (78%, 17 primary and 11 metastatic), and anti-MelanA in 27 cases (75%, 19 primary and 8 metastatic). Although negative in schwannomas, neurofibromas, and malignant peripheral nerve sheath tumors, MUM1 is detected in only one in eight cases of spindle cell and desmoplastic melanomas. With the exception of desmoplastic and spindle cell melanomas, MUM1 appears to be a sensitive and specific immunohistochemical stain for melanocytic lesions and may prove to be a useful addition to the current panel of melanoma markers.
View details for DOI 10.1097/01.MP.0000081726.49886.CF
View details for Web of Science ID 000185084000010
View details for PubMedID 12920225
Antibodies to CD4, CD8, TIA-1, and CD56 are available which perform well in formalin-fixed and paraffin-embedded tissue. While previous studies have investigated CD4 and CD8 subsets in inflammatory skin disease, few have specifically addressed TIA-1 and CD56 reactivity in benign dermatoses. Given that CD8, TIA-1, and CD56 are linked to aggressive lymphoproliferative disorders (i.e. subcutaneous panniculitic T-cell lymphoma, natural killer (NK), and NK/T-cell lymphomas), it would be important to determine their specificity for cutaneous hematologic malignancies. This investigation was undertaken to determine the frequency with which common, benign dermatoses express these four markers. We also sought to determine whether the ratio of CD4- to CD8-positive cells could be used to distinguish among the dermatoses, especially the superficial and deep perivascular ones.Formalin-fixed and paraffin-embedded sections from a variety of common inflammatory dermatoses were stained with antibodies to CD4, CD8, TIA-1, and CD56. Positive reactions were scored as a percentage of the entire mononuclear cell infiltrate.All of the dermatoses represented in the study showed TIA-1- and CD56-positive lymphocyte subpopulations. On a case-by-case basis, the percentage of positive cells varied, and while all cases were positive for TIA-1, many were completely negative for CD56. For TIA-1, the percentage of positive cells ranged from 21 to 59%, and for CD56, from < 1 to 9%. The CD4:CD8 ratio ranged from 1.0 to 6.0 but was never less than 1.0. In addition to lymphocytes, TIA-1 also stained polymorphonuclear leukocytes, eosinophils, and mast cells.TIA-1- and CD56-positive lymphocytes are common participants in routine inflammatory dermatoses, and therefore these markers are not specific for aggressive lymphoproliferative disorders. Using only immunohistochemical data, the ratio of CD4- to CD8-positive lymphocytes could not be used reliably to separate the superficial and deep perivascular dermatoses from one another. Finally, mast cells are positive for TIA-1 and are commonly seen in normal and inflamed skin, and thus TIA-1 is not specific for cytotoxic T lymphocytes.
View details for Web of Science ID 000181633300002
View details for PubMedID 12641788
Recently, we have discovered an endogenous cholinergic pathway for angiogenesis mediated by endothelial nicotinic acetylcholine receptors (nAChRs). Since angiogenesis plays a major role in wound repair, we hypothesized that activation of nAChRs with nicotine would accelerate wound healing in a murine excisional wound model. In genetically diabetic and control mice full-thickness skin wounds (0.8 cm) were created on the dorsum and topically treated over 7 days with either vehicle (phosphate-buffered saline, PBS) or nicotine (10(-8) mol/L, 10(-9) mol/L; each, n = 5). Wound size was measured over 14 days followed by resection, histological analysis, and quantitation of vascularity. In diabetic animals an agonist (epibatidine, 10(-10) mol/L) or antagonist (hexamethonium, 10(-4) mol/L) of nAChRs as well as the positive control basic fibroblast growth factor (bFGF, 25 microg/kg) were also tested. To further study the role of endothelial nAChRs in angiogenesis, we used an ex vivo vascular explant model. In diabetic mice wound healing was markedly impaired. Nicotine significantly accelerated wound healing as assessed by closure rate and histological score. The effects of nicotine were equal to bFGF and were mimicked by epibatidine and blocked by hexamethonium. Histomorphometry revealed increased neovascularization in animals treated with nicotine. Furthermore, capillary-like sprouting from vascular explants was significantly enhanced by nicotine. In conclusion, agonist-induced stimulation of nAChRs accelerates wound healing in diabetic mice by promoting angiogenesis. We have discovered a cholinergic pathway for angiogenesis that is involved in wound healing, and which is a potential target for therapeutic angiogenesis.
View details for Web of Science ID 000176718300013
View details for PubMedID 12107094
View details for Web of Science ID A1996WA82700045