Background: The mechanisms of tumor progression in mycosis fungoides (MF) and Sézary syndrome (SS) are poorly understood. Twist, a transcription factor, is thought to promote solid tumor progression by blocking p53 and inhibiting c-myc-induced apoptosis. Whether Twist expression is correlated to MF/SS stages remains unknown.

Methods: Twist, c-myc and p53 proteins in 68 MF/SS lesions across all T stages were examined by immunohistochemistry, and mRNA levels in peripheral blood CD4+ T-cells from SS patients were measured by QT-PCR.

Results: Positive staining for Twist was found in 12.5% (2/16) of T1 and 33.3% (7/21) of T2 early stage patches/plaques compared to 50.0% (9/18) of T3 tumors and 84.6% (11/13) of T4 erythroderma. Most T4 erythroderma were positive for Twist in dermal lymphocytes, with the strongest staining. Positive staining for c-myc was higher in T3/T4 lesions (29/31, 93.5%) than T1/T2 lesions (25/37, 67.6%, p<0.05), with strongest staining in T3 tumors. Aberrant p53 expression was more common in T3/T4 lesions (8/31; 25.8%) than in T1/T2 lesions (2/37, 5.4%, p<0.05). Twist mRNA was detected in all CD4+ T cells from SS patients but not in normal donors.

Conclusions: Increased Twist protein expression in advanced MF/SS lesions suggests that Twist expression may correlate with MF/SS stages.

A 59-year-old female with rheumatoid arthritis on etanercept therapy presented with a 7-cm-large subcutaneous forearm mass. Multiple smaller nodules subsequently developed on the upper and lower extremities. Except for a new cough, the patient was systemically well. Biopsy of the mass showed sarcoidal type granulomatous inflammation with nodular aggregations of non-necrotizing epithelioid histiocytes in the subcutis. A chest computed tomography (CT) scan showed mediastinal adenopathy consistent with pulmonary sarcoidosis. Etanercept was discontinued, and the patient was started on adalimumab for rheumatoid arthritis control. The cutaneous nodules fully resolved in 6 months with no additional treatment. A 4-month follow-up CT scan showed significant regression of mediastinal adenopathy. The patient has since been maintained on adalimumab therapy for 2 years with no recurrence of sarcoid-like manifestations. Biologic response modifiers targeting tumor necrosis factor alpha (TNFα) are effective treatments of chronic inflammatory conditions such as rheumatoid arthritis and psoriasis. TNFα represents a major cytokine in granuloma formation, and TNFα inhibitors are sometimes efficacious in the treatment of sarcoidosis. Paradoxically, there is a small volume of literature implicating TNFα inhibitors in the development of sarcoid-like disease. We present this case to promote the recognition of TNFα inhibitor-induced sarcoidosis and to illustrate the wide clinicopathologic differential of sarcoidal type granulomas.

Burns AM, Green PJ, Pasternak S. Etanercept-induced cutaneous and pulmonary sarcoid-like granulomas resolving with adalimumab.

Background: Distinguishing keratoacanthoma (KA) and hypertrophic lichen planus (LP) histopathologically can be difficult, and the challenge is compounded by the tendency of KA to arise in association with hypertrophic LP.

Methods: In this pilot study, we compared 18 cases each of KA and hypertrophic LP for proliferation index (MIB-1), p53 staining and the presence of perforating elastic fibers (elastic Verhoeff-van Gieson) to determine the utility of these staining modalities in distinguishing KA from hypertrophic LP.

Results: Proliferation index in KA compared to hypertrophic LP is 88.2 (mean positive MIB-1 cells/×100 field), SD = 56.6 and 47.3, SD = 68.4, respectively. p53 staining in KA compared to hypertrophic LP is 251 (mean positive cells/×100 field), SD = 117 and 158, SD = 119, respectively. Fifteen of eighteen (83%) keratoacanthomata demonstrate perforating elastic fibers compared to 1/18 (6%) for hypertrophic LP.

Conclusion: Proliferation index is not significantly different between KA and hypertrophic LP (p = 0.059). Expression of p53 is increased in KA over hypertrophic LP (p = 0.024). The presence of perforating elastic fibers in KA is significantly different from hypertrophic LP (p < 0.0001) and suggests that elastic Verhoeff-van Gieson staining may be of practical benefit in distinguishing KA from hypertrophic LP in difficult cases.

Bowen AR, Burt L, Boucher K, Tristani-Firouzi P, Florell SR. Use of proliferation rate, p53 staining and perforating elastic fibers in the distinction of keratoacanthoma and hypertrophic lichen planus: a pilot study.

Background: The histopathologic pattern of clonal seborrheic keratosis (SK) is quite similar to the nested pattern of pagetoid Bowen's disease [squamous cell carcinoma in situ (SCCIS)], and differentiation between the two can be challenging, especially when only small pieces are available for interpretation.

Methods: Eleven examples of clonal SK and 13 examples of pagetoid SCCIS were examined histopathologically (tabulating necrotic keratinocytes, suprabasal mitoses, infiltrate, parakeratosis housing plump nuclei, crowding of nuclei) and immunohistochemically (using Ki-67, bcl-2, cytokeratin 7 and cytokeratin 10). Sensitivity, specificity, p-values (Fisher's exact test, two-tailed) and positive/negative likelihood ratios (+LR/−LR) were calculated.

Results: Significant differences were seen with regard to crowding (p = 0.0009) and mitoses (p = 0.0006); however, only complete absence of necrotic keratinocytes or of crowding appeared to be diagnostically convincing for a diagnosis of clonal SK (−LR < 0.01). Significant differences were also seen with bcl-2 (p = 0.0005) and cytokeratin 10 antibodies (p < 0.00001). Both markers displayed a typical nested pattern in clonal SK, nests being bcl-2-positive and cytokeratin 10-negative. Cytokeratin 10-negative nests were the most convincing criterion for differentiation between clonal SK and pagetoid SCCIS (+LR > 10, −LR < 0.01).

Conclusions: The most reliable marker to distinguish clonal SK from pagetoid SCCIS is cytokeratin 10 when it spares nests. Other criteria that assist in the differential diagnosis are bcl-2 expression, absence of crowding and of mitoses.

Böer-Auer A, Jones M, Lyasnichaya OV. Cytokeratin 10-negative nested pattern enables sure distinction of clonal seborrheic keratosis from pagetoid Bowen's disease.

Primary effusion lymphoma, a human herpesvirus 8 (HHV8)-associated lymphoma, is uncommon, and it is usually seen in human immunodeficiency virus (HIV)-infected patients. It presents as a body cavity-based lymphomatous effusion, but several cases of the so-called solid primary effusion lymphoma presenting as solid tumors without associated lymphomatous effusion have been reported. They have similar clinical, histopathological and immunophenotypical features. Most of them have a B-cell genotype. This suggests the solid variant may represent a clinicopathological spectrum of primary effusion lymphoma. We report a case of HHV8-associated lymphoma histopathologically and immunophenotypically mimicking cutaneous anaplastic large cell lymphoma. The patient was a 31-year-old HIV-seropositive man presenting with skin nodules over his right thigh. Biopsy of the nodules showed anaplastic large cells infiltrating the dermis. These malignant cells strongly expressed CD3, CD30 and CD43. Cutaneous anaplastic large T-cell lymphoma was initially diagnosed, but further tests, including immunoreactivity for HHV8 protein and clonal rearrangements of immunoglobulin genes, confirmed the diagnosis of HHV8-associated B-cell lymphoma with aberrant T-cell marker expression. This case provides an example of solid primary effusion lymphoma mimicking cutaneous anaplastic large T-cell lymphoma and highlights the importance of HHV8 immunohistochemistry and molecular tests in the diagnosis of HHV8-associated lymphoma with a cutaneous presentation.

Li M-F, Hsiao C-H, Chen Y-L, Huang W-Y, Lee Y-H, Huang H-N, Lien H-C. Human herpesvirus 8-associated lymphoma mimicking cutaneous anaplastic large T-cell lymphoma in a patient with human immunodeficiency virus infection.

Background: Cutaneous leishmaniasis displays considerable variation in its histopathological and clinical presentation. Clinically, it progresses from a papule into a painless ulcerated and crusted nodule/papule. Microscopically, it progresses from sheets of amastigote-filled histiocytes to granulomatous inflammation.

Methods: The study was conducted on 145 skin biopsies from untreated patients with histopathological and/or clinical suspicion of cutaneous leishmaniasis in Lebanon, Syria and Saudi Arabia (1992–2010). The pre-biopsy clinical diagnosis and demographic data were collected. Biopsies were evaluated for the major microscopic pattern, and the parasitic index (PI) was also determined. Diagnosis was confirmed by polymerase chain reaction (PCR) followed by molecular sub-speciation.

Results: Of the 145 patients, 125 were confirmed as cutaneous leishmaniasis by PCR. Eighteen cases presented with a pre-biopsy clinical diagnosis other than cutaneous leishmaniasis that ranged from dermatitis to neoplasm. Of the 125 cases, 57 showed a major histopathological pattern other than cutaneous leishmaniasis. Identification of amastigotes was equivocal (PI ≤1) in 38 of the 57 cases. Of interest, all the 18 cases with a pre-biopsy clinical diagnosis other than cutaneous leishmaniasis also showed atypical histopathology for cutaneous leishmaniasis.

Conclusions: The manifestations of cutaneous leishmaniasis are broad and may mimic other inflammatory and neoplastic diseases. Pathologists and dermatologists should be aware of such pitfalls and can utilize PCR to confirm the diagnosis of leishmaniasis.

Saab J, Fedda F, Khattab R, Yahya L, Loya A, Satti M, A-G Kibbi, Houreih MA, Raslan W, El-Sabban M, Khalifeh I. Cutaneous leishmaniasis mimicking inflammatory and neoplastic processes: a clinical, histopathological and molecular study of 57 cases.

Background: Secondary angiosarcoma and benign but microscopically atypical vascular proliferations (herein referred to as atypical vascular lesion or AVL) are rare consequences of radiation therapy and/or chronic lymphedema most commonly seen in breast cancer patients. Differentiating angiosarcoma from AVL can be difficult due to overlapping clinical and microscopic features. Recently, amplification of MYC has been associated with 55–100% of secondary angiosarcomas but is reportedly absent in AVL. We examined a series of secondary angiosarcoma and AVL for MYC amplification by fluorescence in situ hybridization (FISH) and expression by immunohistochemistry to investigate the diagnostic utility for discriminating angiosarcoma from AVL.

Methods: Cases of secondary angiosarcoma (n = 8) and AVL (n = 4) were retrieved from our archives and examined by FISH and immunohistochemistry.

Results: All angiosarcoma cases (8/8 = 100%) demonstrated high-level MYC amplification by FISH, whereas all AVLs (0/4 = 0%) were negative for MYC amplification. Additionally, all angiosarcoma cases (8/8 = 100%) demonstrated nuclear positivity for MYC, whereas all AVLs (0/4 = 0%) were negative.

Conclusion: Amplification of MYC and nuclear expression of MYC is present in secondary angiosarcoma but not AVL. These ancillary tests can be useful to distinguish angiosarcoma from AVL in difficult cases.

Fernandez AP, Sun Y, Tubbs RR, Goldblum JR, Billings SD. FISH for MYC amplification and anti-MYC immunohistochemistry: useful diagnostic tools in the assessment of secondary angiosarcoma and atypical vascular proliferations.

A 62-year-old man presented with a 2-year history of a 2-cm cystic mass involving his occiput. There had been recent enlargement, and the clinical impression was that of a pilar cyst. Histopathological sections showed a partially dermal solid and cystic proliferation. The tumor contained areas of glandular differentiation with cuboidal to columnar cells lining luminal and cystic spaces. A concurrent spindle cell proliferation was seen interspersed between glands and also formed broad, cellular sheets of cells. The stroma was sclerotic and without chondroid or myxoid elements. Immunohistochemistry showed that the spindled cells expressed S100 protein, cytokeratin and smooth muscle myosin. The immunohistochemical profile and the relationship with ductal elements supported myoepithelial differentiation. The proliferation warranted the diagnosis of myoepithelioma arising from a hidradenoma, which to our knowledge has not been previously described. In addition to discussing this case, we provide a brief review of epithelial–myoepithelial neoplasms encountered in the skin.

Jakate K, Wong K, Sirbovan J, Hanna W. Cutaneous myoepithelioma arising within hidradenoma of the scalp.

The clinical and histopathological features of cutaneous herpes simplex virus (HSV) infection have been well described. Genital herpetic infections are largely induced by HSV type 2, but 30% of cases can be caused by HSV type 1. Immunocompromised patients are known to exhibit atypical patterns of clinical presentation with variable lesion morphology and anatomic location. A subset of patients may show morphology such as nodules or verrucous lesions. Analogously, some biopsy specimens may show unusual microscopical features, such as a lack of keratinocyte cytopathology, lymphocyte infiltration or vasculopathic changes that are expected irrespective of the patient's immune status. We present the case of a patient carrying a previous diagnosis of pemphigus vulgaris, status posttreatment with methotrexate and prednisone, who developed a perineal ulcer exhibiting significant numbers of plasma cells, many of which were cytologically atypical. This morphology was suggestive of a hematopoietic malignancy. Immunoperoxidase staining for HSV decorated a focal collection of keratinocytes that lacked appreciable viral changes expected of HSV infection.

Boyd AS, Zwerner JP, Miller JL. Herpes simplex virus-induced plasmacytic atypia.

Primary cutaneous amyloidosis includes several forms of localized amyloidosis characterized by superficial amyloid deposits occurring at or near the dermal–epidermal junction in the absence of systemic involvement. Primary cutaneous amyloidosis of the auricular concha and external ear represents a rarely described variant. There have been 27 cases reported in the English language literature, and herein we report 17 additional cases. This article demonstrates that the amyloid observed in this context is generally positive for Congo red, crystal violet and thioflavin T. It also expresses cytokeratin 34ßE12 via immunohistochemistry. Our immunohistochemical results and review of the literature suggest that the amyloid in amyloidosis of the external ear is the result of basal keratinocyte degeneration and does not signify deposition from a systemic or generalized process.

Wenson SF, Jessup CJ, Johnson MM, Cohen LM, Mahmoodi M. Primary cutaneous amyloidosis of the external ear: a clinicopathological and immunohistochemical study of 17 cases.

Granulomatous cutaneous reactions are well described in association with T-cell non-Hodgkin lymphoma and Hodgkin lymphoma, but are rarely seen in association with B-cell non-Hodgkin lymphoma or leukemia. We report a case of a 65-year-old woman with B-cell chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) who presented with multiple, tender, firm pink papules on the face, upper trunk and upper extremities 6 years after diagnosis of CLL. Biopsy revealed both palisading granulomatous dermatitis consistent with actinic granuloma and a dense perivascular lymphocytic infiltrate consistent with the patient's known history of leukemia. This is an unusual manifestation of cutaneous B-cell CLL that is rarely seen.

Kauffman JA, Ivan DS, Cutlan JE, Hymes SR. Actinic granuloma occurring in an unusual association with cutaneous B-cell chronic lymphocytic leukemia.