Ectopic immature renal tissue in a lumbosacral lipoma: pathologic and radiologic findings.

Ectopic immature renal tissue was found in a lumbosacral subcutaneous lipoma with intradural extension in a 6-day-old female with spina bifida. No additional neurologic or renal anomalies were found. Ectopic renal tissue is an extremely rare finding. Histopathologic and MRI results from this case are presented and the possible significance of ectopic renal tissue in relation to the origin of extrarenal Wilms' tumors is discussed.