[Congenital mesoblastic nephroma (Bolande's tumor). Prenatal diagnosis].

The authors report a new case of the antenatal ultrasound diagnosis of a congenital mesoblastic nephroma (also called Bolande's tumor) at 33 weeks of amenorrhea. This tumor was found to be associated with acute hydramnios involving premature labor and fetal death by respiratory embarrassment. Congenital mesoblastic nephroma is a very rare entity but is the predominant renal neoplasm in the immediate neonate period. The differential diagnosis between Bolande's tumor and nephroblastoma (Wilm's tumor) is now clear since histopathological features have been precisely described by Bolande. Clinical and pathological features of the renal disease are discussed. The prognosis is excellent for most cases requiring only surgical treatment (nephrectomy).