Leukemia cutis occurs when the skin is infiltrated by a malignant proliferation of leukocytes. There are several subtypes, including skin involvement associated with acute lymphoblastic leukemia (ALL), acute myelogenous leukemia (AML), chronic myelogenous leukemia (CML), and chronic lymphocytic leukemia (CLL). Leukemia cutis portends a poorer prognosis.

The frequency of skin involvement in leukemia is unknown. Approximately a quarter-million Americans are affected by leukemia at any time. Leukemia is the most common malignancy of childhood, and boys are more likely to develop the disease than girls. Ninety percent of leukemias are diagnosed in adults and typically present after age 50.