The morphologic and immunohistochemical diversity of malignant melanoma is well known to pathologists but despite this widespread awareness the diagnosis remains a constant challenge, particularly when a noncutaneous or metastatic tumor is evaluated by fine-needle aspiration cytology. We present a case of the small cell variant of malignant melanoma mimicking lymphoma in a 78-year-old previously healthy male who presented with multiple pulmonary masses and a right-sided pleural effusion. This particular case was also immunoreactive for the hematopoietic marker CD43, a feature not previously reported in malignant melanoma. Cytologic, histologic, and immunohistochemical features of this case are presented and discussed.
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