Leukemia cutis.

Leukemia cutis is an uncommon manifestation of leukemia that is strongly associated with the presence of extramedullary disease at other sites. Patients usually present with leukemia cutis concomitantly with systemic leukemia or after leukemia has been diagnosed. Acute monocytic, myelomonocytic, and the T-cell leukemias show the highest incidence of leukemia cutis. The lesions show varied morphology and can be difficult to distinguish both clinically and histopathologically from nonspecific cutaneous lesions, which occur much more frequently. Immunohistochemistry is useful in making the distinction between them. The prognosis in leukemia cutis is generally poor; the best results have been achieved with a combination of systemic and local therapy.