Merkel cell carcinoma after chronic lymphocytic leukemia: case report and literature review.

Increasing evidence supports an association of Merkel cell carcinoma (MCC) with immunodeficiency and neoplasia, and the management and outcome of these patients requires study. This report describes a 72-year-old man with newly diagnosed chronic lymphocytic leukemia (CLL) who developed MCC of his right upper extremity and died of bone marrow metastases at 8 months. In the five previously reported cases of MCC after CLL, a shorter time interval between the diagnosis of CLL and the onset of MCC was associated with a better prognosis. In contrast, in this case the near simultaneous onset of CLL and MCC was followed by a rapid, lethal outcome.