Granulocytic sarcoma presenting as a diffuse renal mass before hematological manifestations of acute myelogenous leukemia.

Granulocytic sarcoma is a rare tumor composed of granulocytic precursor cells. The most common sites of involvement include the bones, soft tissue, lymph nodes and skin. Granulocytic sarcoma usually develops as a delayed manifestation of the disease process in patients with known acute myelogenous leukemia. To our knowledge we report the first case of renal granulocytic sarcoma presenting as the first sign of acute myelogenous leukemia. Computerized tomography and magnetic resonance imaging revealed diffuse nonspecific global tumor infiltration of the kidney and ureter. Renal granulocytic sarcoma was diagnosed on open renal biopsy and acute myelogenous leukemia on bone marrow biopsy. There has been partial response to combination chemotherapy. Renal granulocytic sarcoma may diffusely involve the kidney as the only manifestation of acute myelogenous leukemia and it should be included in the differential diagnosis of the many disease entities with global renal involvement since initial treatment is combination chemotherapy.