Merkel cell carcinoma in the setting of chronic lymphocytic leukemia

BACKGROUND Merkel cell carcinoma (MCC) is a rare, aggressive, primary skin cancer that usually occurs in elderly white people on the sun-exposed areas of skin. Chronic lymphocytic leukemia (CLL) is a low-grade, clonal, B-cell, lymphoproliferative disorder that also usually affects older adults. CLL has been associated with multiple other secondary malignancies, especially skin cancer. OBJECTIVE To further understand the characteristics and behavior of MCC in the setting of concomitant CLL. MATERIALS AND METHODS We identified patients with diagnoses of both MCC and CLL who were seen at the Mayo Clinic (Rochester, MN) from January 1, 1976, to December 31, 2008, and retrospectively reviewed the charts of the identified patients. RESULTS Seven patients received diagnoses of MCC and CLL. Five of these patients appeared to have higher rates of recurrence, metastasis, and mortality than patients with MCC but not CLL. CONCLUSIONS MCC may behave more aggressively in the setting of concomitant CLL, but more studies are needed to definitively evaluate the characteristics and behavior of MCC in these patients. The authors have indicated no significant interest with commercial supporters.