Collision of chronic lymphocytic leukemia/small lymphocytic lymphoma and melanoma.

A 39-year-old man noted a pigmented lesion on his back that had been growing for ;1 year. A punch biopsy demonstrated malignant melanoma, nodular type. He was also found to have a white blood cell count of 45.8 3 10/mL and palpable axillary, cervical, and inguinal lymph nodes. The blood was sent for flow cytometry and demonstrated a population of small CD19 B cells that were l light chain restricted, CD5, CD10, and CD23 consistent with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). Surgical pathology received bilateral axillary contents and a wide excision of the melanoma on the back. The lymph nodes grossly demonstrated areas that were pink-tan and fish-fleshy and other areas that were darkly pigmented. Of the 84 lymph nodes that were microscopically evaluated, 43 were involved by melanoma, and all were involved by CLL/SLL.