Spontaneous kidney rupture with incidental renal cell cancer in patient with Castleman's disease.

A 65-year-old man with a history of Castleman's disease presented with abdominal and right flank pain. He denied any recent trauma. On admission, his hemoglobin was 7.0 g/dL, and the blood urea nitrogen and serum creatinine concentration was 30 and 1.62 mg/dL, respectively. Computed tomography of the patient's abdomen revealed a large right perinephric hematoma. The patient underwent emergency nephrectomy. Microscopic examination of the specimen revealed an incidental renal cell carcinoma.