[Myeloid sarcoma of the kidney: a case report].

A 40-year-old man was referred to our department for left renal tumor pointed out on a checkup ultrasonography. CT (computed tomography) and MRI (magnetic resonance imaging) demonstrated left renal tumor, clinically T2N0M0. Percutaneous renal needle biopsy was performed because of malignant lymphoma was suspected. Pathological diagnosis was malignant tumor. However, malignant lymphoma could not denied. Therefore, left nephrectomy was performed retroperitonealy. Histological examination revealed myeloid sarcoma of the kidney. Myeloid sarcoma is a rare tumor composed of leukemia cells and usually progresses to acute myelogenous leukemia. To our knowledge, our case is the first report of myeloid sarcoma of the kidney in Japan.