[Merkel cell carcinoma in a patient with chronic lymphocytic leukemia].

Merkel cell carcinoma (MCC) is an infrequent neuroendocrine tumor of the skin with a high potential for local recurrence, lymphatic dissemination and distant dissemination. We present a case of MCC in a male patient with chronic lymphocytic leukemia (CLL). The immunosuppression induced by the leukemia or by the chemotherapy could play a pathogenic role in the association of these diseases. Positron emission tomography (PET) was a useful staging technique in this patient, and made the differential diagnosis of the lymph node involvement from MMC and CLL possible.