[Acute promyelocytic leukemia accompanied by scrotal Fournier's gangrene during ATRA treatment and relapsed as external ear tumor].

A 43-year-old man was admitted because of gingival bleeding. A diagnosis of acute promyelocytic leukemia (APL) was made. He was given combination chemotherapy including all-trans retinoic acid (ATRA). During the myelosuppression stage, the patient developed Fournier's gangrene of the scrotum. He achieved complete remission and underwent a hemicastration procedure. Seven months later, bilateral external ear tumors developed. Biopsy specimens of the tumors revealed infiltration of APL cells. A second remission was obtained by chemotherapy including ATRA. However, bilateral ear tumors developed again 5 months later despite indications of normal marrow without proliferation of leukemic blasts. Irradiation successfully reduced the ear tumors, but the patient died of cerebral hemorrhage from a left frontal extramedullary tumor. This was a rare case of APL accompanied by Fournier's gangrene of the scrotum during ATRA treatment, and by extramedullary tumors of the external ear and brain during leukemic relapse.