[A case of primary osteogenic sarcoma of the kidney].

Extraosseous osteogenic sarcoma can occur anywhere in the body, but it is exceedingly rare to find this malignancy in renal tissue. A review of the literature revealed only 16 cases which appeared to be clearly identifiable as malignant extraosseous bone-forming sarcoma of the kidney and our report presents 17th case. The patient was a 67-year-old oriental woman. In March 1994, abdominal plain radiographs showed several dense calcifications in the left flank at another hospital. In May 1995, a huge tumor appeared in the left upper quadrant, so she was admitted to department of Internal Medicine of our institute for further examination. As the subsequent abdominal CT scan showed a huge renal tumor with accompanying calcifications, she was transferred to department of Urology. We diagnosed this tumor to be a huge renal cell carcinoma featuring calcifications and performed left nephrectomy. Microscopically, this tumor demonstrated predominantly osteoblast-like tumor cells coupled with osteoid and bone formation. Its histological appearance was compatible with that of osteogenic sarcoma. Bone scan and skeletal radiograph presents to evidence of malignancy, which led to our diagnosis of primary osteogenic sarcoma of the left kidney. Two months after nephrectomy, we found a large palpable recurrent mass in the left upper quadrant of the abdomen. Although two courses of cisplatin were then administered, her condition deteriorated until death on October 25, 1995, about four months after nephrectomy.