Leukemia Cutis

A 67-year-old woman noted the appearance of several non-tender, rock-hard, purple-colored nodules on her legs. Her past medical history was significant for distant non-Hodgkin lymphoma.

Key point: The violaceous color and configuration of the skin lesions suggests 3 things: mycobacterial infection, cutaneous lymphoma, and leukemia cutis. A biopsy revealed dense aggregates of immature leukocytes (blasts), suggesting an aggressive leukemia. Bone marrow aspiration was confirmatory.

Treatment: The patient is undergoing chemotherapy at the direction of a hematological oncologist.

Note: Once leukemia involves the skin, the prognosis is often quite grave. The most common cause of leg nodules, erythema nodosum, is expected to be painful.