Bilateral rhabdomyomatous tumor relapsed as typical triphasic Wilms' tumor.

The authors report on a child affected with bilateral renal tumor, which was treated with cancer chemotherapy before and after surgery. Twenty-eight months after the discontinuance of therapy, a neoplasm was disclosed in the left kidney and then removed. Histologically, the bilateral tumor excised by the first surgery could be classified as biphasic Wilms' tumor, rhabdomyomatous variant, whereas the neoplasm removed by the second surgery was the typical triphasic Wilms' tumor. The authors suggest that preoperative chemotherapy might have played a role in the histologic changes of the initial tumor. Nonetheless, it is also tempting to postulate that the two histologic variants of Wilms' tumor could have occurred in the patient in spite of any treatment.