Fine-needle aspiration diagnosis of unusual cutaneous neoplasms of the scalp in HIV-infected patients: a report of two cases and review of the literature.

We report on two unusual, non-AIDS-defining scalp neoplasms, Merkel-cell carcinoma (MCC) and malignant melanoma, in 2 men with acquired immunodeficiency syndrome (AIDS). In the first patient, metastatic MCC was initially diagnosed by fine-needle aspiration (FNA) of a posterior cervical lymph node, based on the cytomorphology and the characteristic immunohistochemical and ultrastructural features. No skin lesion was initially apparent, but a 0.3-mm scalp primary was found during the ensuing neck dissection. In the second patient, recurrent and metastatic malignant melanoma from a Breslow 1.3-mm scalp primary was diagnosed by FNA. Both patients developed generalized disease in a relatively short time, despite their small primaries. These cases illustrate the occurrence of Merkel-cell carcinoma and melanoma in AIDS patients, and stress the need to consider these unusual cutaneous neoplasms when evaluating lymph node FNA samples from HIV-positive patients, especially since both may present as metastases from clinically occult primaries.