Multicentric bilateral renal cell carcinomas and a vascular leiomyoma in a child.

We report a unique case of multicentric bilateral renal cell carcinomas and a simultaneous large renal vascular leiomyoma in an 11-year-old child with sickle cell anemia. The patient presented with several episodes of massive hematuria. Abdominal sonography and computed tomography demonstrated bilateral renal neoplasms and the patient was clinically thought to have bilateral Wilms' tumor. An initial biopsy of the lower pole of right kidney revealed a renal cell carcinoma. Accordingly, bilateral renal angiography followed by right total nephrectomy and left upper pole partial nephrectomy were performed. Pathologic studies showed multicentric, bilateral renal cell carcinomas (two in the right kidney and one in the left kidney), of clear, granular, and oncocytic cell types. A simultaneous large vascular leiomyoma was also present in the right kidney. The smooth muscle nature of the leiomyoma was determined by light microscopy, immunohistology, and electron microscopy. The diagnostic difficulties in distinguishing them from other renal tumors are discussed.