Atypical fibroxanthoma (AFX) is an uncommon dermal-based neoplasm arising on the sun-damaged skin of elderly people. Clear cell AFX is a rare variant with only 12 cases reported until the present date, all of them as case reports, except for 1 small series of 3 cases. The authors report 6 new cases and review the literature with special emphasis on the differential diagnosis. The clear cell variant represents 5% of AFX from their files. Histopathologically, it consists of sheets of epithelioid, pleomorphic cells, intermixed with a varying number of giant multinucleated and spindle cells, the latter arranged in a fascicular pattern. All cell types predominantly exhibit a clear, microvacuolated cytoplasm with well-demarcated cell borders. The clinical and immunohistochemical features of this variant are similar to those of the classic type. Clear cell AFX must be differentiated from other cutaneous clear cell neoplasms, some of them with an aggressive clinical behavior, including clear cell melanoma, primary cutaneous and metastatic clear cell carcinomas, clear cell sarcoma, pleomorphic liposarcoma, tumor of perivascular epithelioid cells, and distinctive dermal clear cell mesenchymal neoplasm. The clinical presentation and immunohistochemical profile play a key role in the differential diagnosis.

Several types of vasculitis have been described in patients with human immunodeficiency virus infection. Erythema elevatum diutinum is a rare variant of cutaneous leukocytoclastic vasculitis which, with the exception of the case reported herein, has been described only once in human immunodeficiency virus-infected patients. Our male patient, a longtime intravenous drug abuser, had cutaneous lesions, closely resembling Kaposi's sarcoma, on the extensor surfaces of the lower extremities. Cutaneous biopsy specimens, however, demonstrated leukocytoclastic vasculitis with fibrinoid necrosis of the vessel walls and areas of basophilic degeneration of collagen bundles in early lesions, whereas late lesions showed dense diffuse fibrosis with proliferation of dermal spindle cells and some foci of residual leukocytoclastic vasculitis. Oral therapy with dapsone resulted in marked clearing of the cutaneous lesions within few days. This case raises the necessity of histologic confirmation for all cases of suspected Kaposi's sarcoma in patients with acquired immunodeficiency syndrome. We discuss the possible pathogenesis of leukocytoclastic vasculitis in human immunodeficiency virus-infected patients.

We report a case of localized epidermal necrolysis that developed 24 hours after an intravenous injection of vinblastine. Clinically, the lesions consisted of erythematous macules, vesicles, and bullae with a linear arrangement over the injected vein. Histologically, the lesions showed features closely resembling erythema multiforme (epidermal necrolysis). We discuss the pathogenesis of this curious cutaneous drug reaction and review the literature concerning local cutaneous complications associated with intravenously administered chemotherapeutic agents.

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