Neuroendocrine (Merkel cell) carcinoma with an intraepidermal component.

We present 11 cases of primary neuroendocrine (Merkel cell) carcinoma of the skin with an intraepidermal component that were identified in a larger review of Merkel cell carcinomas. Among these is a case with a follow-up of over 11 years in which the primary lesion appeared as bowenoid dysplasia, with subsequent recurrences as intraepidermal Merkel cell carcinoma with focal tubular differentiation, and then with dermal invasion and lymph node metastasis. In addition to immunohistochemical markers commonly used in the identification of Merkel cell carcinomas (neuron-specific enolase and cytokeratin), these tumors stained with Ber-EP4, an immunohistochemical marker used to identify carcinomas. We believe that these histopathologic and immunohistochemical features further confirm that Merkel cell carcinomas represent an epithelial tumor with the potential for neuroendocrine and adnexal differentiation.

Iontophoresis of vinblastine into normal skin and for treatment of Kaposi's sarcoma in human immunodeficiency virus-positive patients. The Military Medical Consortium for Applied Retroviral Research.

BACKGROUND: Patients who test positive for human immunodeficiency virus type 1 (HIV-1) and who have disfiguring and/or painful cutaneous lesions of Kaposi's sarcoma (KS) may not be candidates for systemic chemotherapy and/or immunotherapy. Intralesional vinblastine sulfate, as a single-agent chemotherapeutic drug, has been used with some success to treat KS in patients who are HIV-1 positive. However, some patients may not tolerate the pain associated with injection of vinblastine. Transcutaneous iontophoresis of vinblastine was evaluated for therapy of KS in HIV-1-infected patients. Prior to therapy of patients, we iontophoresed vinblastine into the normal skin of volunteers who were not infected with HIV-1 to document the clinical and histologic features that occurred. OBSERVATIONS: Iontophoresis produced a localized erythematous papular eruption in non-HIV-infected volunteers but not in HIV-1-infected patients. Histologic changes in the biopsy specimens taken from non-HIV-infected volunteers consisted primarily of scattered necrotic keratinocytes and a mild to moderate superficial lymphohistiocytic infiltrate. Thirty-one lesions of KS were treated with partial to complete clearing and symptomatic improvement. CONCLUSION: Clinical and histologic features of iontophoresed normal skin suggest an immunologic mechanism of action. Iontophoresis of vinblastine for KS is well tolerated and results in symptomatic improvement as well as varying degrees of clearing of the lesions.

Recent advances and controversies concerning adnexal neoplasms.

This article reviews the diagnostic clinical and histologic features of a group of adnexal tumors, including papillary eccrine adenoma, adenoid cystic carcinoma, Merkel's cell carcinoma, aggressive digital papillary adenoma (and adenocarcinoma), Bowen's disease, intraepidermal epithelioma, microcystic adnexal carcinoma and related tumors, and subcutaneous trichoepithelioma. These are adnexal tumors either often not recognized, because of their rarity, or the origin, biologic potential, and classification of which have been controversial.