Leukemia cutis presenting clinically as disseminated herpes zoster in a patient with unrecognized acute promyelocytic leukemia.

A 46-year-old man presented with a two-week history of fatigue, fevers, and multiple nonhealing ulcers on his abdomen and back. He also had several dermatomal plaques clinically consistent with multifocal herpes zoster. Biopsy revealed large atypical myeloid cells dissecting through the dermis as well as marked papillary edema reminiscent of Sweet's syndrome. Blood work revealed an elevated white count (35-10(9) cells/L) with 11 percent blasts. Fluorescence in situ hybridization demonstrated a t(15;17) rearrangement diagnostic of M3 acute nonlymphocytic leukemia/acute promyelocytic leukemia. Chemotherapy was initiated, but the patient became septic and expired within two weeks. Acute promyelocytic leukemia cutis is exceedingly rare with only 24 previously reported cases, all of which occurred following treatment with all-trans retinoic acid, which is thought to induce the dermal tropism. The authors believe this is the first reported case of acute promyelocytic leukemia initially presenting with cutaneous involvement. The case is also notable for the Sweet's-like features of the infiltrate.