[A case of congenital mesoblastic nephroma in adulthood].

A 20-year-old man was referred to our hospital with a complaint of asymptomatic macrohematuria. A diagnosis of a right renal tumor was made after several radiographic examinations and right radical nephrectomy was performed. Histopathologically the tumor was a congenital mesoblastic nephroma. Congenital mesoblastic nephroma is a relatively rare renal tumor predominantly of childhood. Occurrence in adults is exceedingly rare and 18 cases have been reported to date.