Primary cutaneous aggressive epidermotropic cytotoxic T-cell lymphomas: reappraisal of a provisional entity in the 2016 WHO classification of cutaneous lymphomas.

Primary cutaneous CD8-positive aggressive epidermotropic T-cell lymphoma is a rare and poorly characterized variant of cutaneous lymphoma still considered a provisional entity in the latest 2016 World Health Organization Classification of Cutaneous lymphomas. We sought to better characterize and provide diagnostic and therapeutic guidance of this rare cutaneous lymphoma. Thirty-four patients with a median age of 77 years (range 19-89 years) presented primarily with extensive annular necrotic plaques or tumor lesions with frequent mucous membrane involvement. The 5-year survival was 32% with a median survival of 12 months. A subset of 17 patients had a prodrome of chronic patches prior to the development of aggressive ulcerative lesions. We identified cases with lack of CD8 or αß T-cell receptor expression yet with similar clinical and pathological presentation. Allogeneic stem cell transplantation provided partial or complete remissions in 5/6 patients. We recommend the term primary cutaneous aggressive epidermotropic cytotoxic T-cell lymphoma as this more broad designation better describes this clinical-pathologic presentation, which allows the inclusion of cases with CD8 negative and/or αß/γδ T-cell receptor chain double-positive or double-negative expression. We have identified early skin signs of chronic patch/plaque lesions that are often misdiagnosed as eczema, psoriasis, or mycosis fungoides. Our experience confirms the poor prognosis of this entity and highlights the inefficacy of our standard therapies with the exception of allogeneic stem cell transplantation in selected cases.

Clinical presentation, immunopathology, and treatment of juvenile-onset mycosis fungoides: a case series of 34 patients.

BACKGROUND: Mycosis fungoides (MF), the most common form of cutaneous T-cell lymphoma, typically presents in middle-aged to elderly individuals. OBJECTIVE: We sought to study the demographics, clinicopathologic features, treatment response, and prognosis of patients with biopsy-proven MF diagnosed before 20 years of age. METHODS: Patients were identified from a prospectively collected database for retrospective analysis. RESULTS: Of 1902 patients with MF, 34 had juvenile-onset MF: 41% were stage IA, 56% were stage IB, and 3% were stage IIB at diagnosis. The male to female ratio was 1.1:1. The median age of symptom onset was 9 years (range 3-19 years), with a delay in diagnosis between 1 month and 14 years. Patients primarily presented with hypopigmented (53%), hyperpigmented (29%), and pink-violaceous (41%) patches/plaques. Immunohistochemistry revealed 39% with CD8(+) immunophenotype, 67% of which had hypopigmented lesions. The phototherapy response rate in 21 patients was 81%. All patients who completely responded to narrowband ultraviolet B phototherapy had hypopigmented MF. LIMITATIONS: This is a single cancer center study. CONCLUSION: Juvenile-onset MF presents with early-stage disease with an overrepresentation of hypopigmented MF and CD8(+) immunophenotype. Narrowband ultraviolet B is an effective treatment option for juveniles, especially for those with the hypopigmented variant.

Pigmented extramammary Paget disease of the thigh mimicking a melanocytic tumor: report of a case and review of the literature.

IMPORTANCE: Extramammary Paget disease (EMPD) is an uncommon tumor that presents in apocrine-rich skin as an irregular, pruritic plaque. Histopathologically, EMPD consists of an intraepidermal proliferation of atypical epithelioid cells. Rarely, the tumor cells contain intracytoplasmic melanin pigment, and the lesion clinically and histopathologically can mimic a melanocytic proliferation. OBSERVATIONS: A 51-year-old female with a history of breast carcinoma presented with a pigmented patch on her right thigh of 6 months duration. The clinical impression was an atypical melanocytic nevus. Histopathologic examination revealed an intraepidermal proliferation of epithelioid cells along the dermal-epidermal junction with pagetoid migration. The tumor cells exhibited increased cytoplasm containing conspicuous melanin pigment and enlarged oval-irregular nuclei. Immunohistochemical studies showed the tumor cells to be strongly and diffusely positive for cytokeratin 8/18, cytokeratin 7 and p63; focally and weakly positive for epithelial membrane antigen (EMA), but negative for cytokeratin 5/6, Cam5.2, carcinoembryonic antigen (CEA), human melanoma black 45 (HMB-45), tyrosinase and Sox-10, supporting the diagnosis of pigmented EMPD. The lesion was subsequently excised, and the patient is free of disease after 24 months. CONCLUSION: We present this unusual case of pigmented EMPD arising on the thigh to draw attention to the entity and to underscore the potentially misleading clinical, histopathologic and immunophenotypic features that mimic other cutaneous intraepidermal lesions.

Metastatic basal cell carcinoma exhibits reduced actin expression.

Basal cell carcinoma is the most common malignancy in Caucasian individuals. Metastatic basal cell carcinoma is extremely rare (with a rate estimated as 0.03%). Actin has been detected in aggressive forms of basal cell carcinoma, but their expression in metastatic lesions is not known. We compared the expression of actin and actin-related cytoskeletal proteins in relatively less aggressive basal cell carcinoma (nodular), aggressive basal cell carcinoma (infiltrative/morpheaform), and metastatic basal cell carcinoma. We studied 12 cases of nodular basal cell carcinoma, 10 cases of infiltrative basal cell carcinoma, and 10 cases of metastatic basal cell carcinoma with immunohistochemistry for alpha-smooth muscle actin, calponin, myosin, and E-cadherin. Expression was interpreted as positive when at least 5% of the tumor exhibited at least weak expression. Five of the ten patients with metastatic basal cell carcinoma had an antecedent history of radiotherapy. Actin was present in 3 of 12 (25%) of the nodular, all 10 of the infiltrative, and 3 of 10 of the metastatic basal cell carcinomas (P<0.05 for metastatic vs infiltrative and nodular vs infiltrative). Calponin was present in 50% of the nodular, 60% of the infiltrative, and 30% of the metastatic basal cell carcinomas (not statistically significant). Myosin expression was not detected in any of the cases. E-cadherin was present in 75% of the nodular, 70% of the infiltrative, and all of the metastatic basal cell carcinomas (P<0.05 for metastatic vs nodular). Our results suggest that increased actin may contribute to local invasiveness, but it is lost in the metastatic phenotype. History of previous radiotherapy may contribute to development of the metastatic phenotype.