[An autopsy case of pulmonary embolism due to renal angiomyolipoma in an elderly woman].

An 86-year-old woman with a 13-year history of hypertension was admitted because of consciousness disturbance, hypotension, tachycardia, and cyanosis at her extremities. Enhanced computed tomography showed a thrombus in the truncus pulmonalis and right pulmonary artery, and also showed a left renal mass and a right renal cyst. Under a diagnosis of pulmonary embolism we started anticoagulant therapy, but the patient died five days after admission. At autopsy, a saddle-like thrombus was found in the truncus pulmonalis and bilateral trunks of pulmonary arteries. Microscopic examination showed smooth muscle cells in the thrombus. We could not find any other thrombus in the inferior vena cava, intrapelvic veins, nor in veins of lower extremities by milking. We also found tumors in both kidneys. Microscopically all tumors were diagnosed as angiomyolipoma. There were many fibrin thrombi in the sinuses of the tumors but there was no evidence of malignancy. We finally diagnosed pulmonary embolism due to renal angiomyolipoma because there was no other thrombus origin and microscopically the same smooth muscle cells were found both in the renal tumor and the pulmonary thrombus. There is only one case report concerning pulmonary embolism due to renal angiomyolipoma which happened during operative treatment. The treatment method of renal angiomyolipoma is determined by tumor size and symptoms, and usually intensive treatment is not performed in cases without symptoms. Our patient had no symptoms until the onset of severe complication of pulmonary embolism, suggesting that radical treatment is necessary for renal angiomyolipoma with a thrombus even when there are no symptoms.