Granulocytic sarcoma of the testis.

Granulocytic sarcoma is a rare tumor composed of neoplastic blood cells, typically occurring during the course of, or before the onset of, acute nonlymphoblastic leukemia. We present a case of a 37-year-old man with acute testicular pain who was found to have a testicular mass diagnosed as granulocytic sarcoma (GS). Because GS virtually always progresses to leukemia, he underwent postoperative radiotherapy and chemotherapy. He was free of disease 6 months after treatment. This case highlights a rare hematologic cancer that urologists and pathologists should be aware of because it can present as a testicular mass.