[Giant solitary fibrous tumor of a kidney: a case report].

Renal solitary fibrous tumor (SFT) has been reported infrequently. We report a case in a 39-year-old woman with a 9-month history of sense of abdominal fullness. Computed tomography revealed well-encapsulated heterogeneous tumors involving the lower pole of the left kidney with left renal vein extension. The tumors measured approximately 20 cm in diameter and displaced adjacent organs. We performed preoperative transcatheter arterial embolization of the left renal artery. Left nephrectomy with complete tumor resection was achieved without major complications. The tumors were well-circumscribed and composed of spindle cells in a collagenous stroma. Immunohistochemistry showed reactivity for CD34 and bcl-2. Immunohistochemical stains for c-kit and CD10 were negative. A diagnosis of SFT was made based on light microscopy and immunohistochemistry. The patient is alive with no evidence of disease 6 months after the operation. This case is the largest renal SFT in the Japanese literature.