Familial synchronous bilateral teratoid Wilms tumor with elevated alpha-fetoprotein level.

Familial Wilms tumor is a rare entity that accounts for only 1-2% of all Wilms tumor cases, with an earlier age of onset and an increased frequency of bilateral tumors. Teratoid Wilms tumor is a variant of nephroblastoma with a predominance of heterologous tissues comprising more than 50% of the tumor volume. Wilms tumor does not usually secrete any specific tumor marker and all teratoid Wilms tumor cases previously reported were sporadic non-secreting neoplasms. Here we describe an infant with familial synchronous bilateral teratoid Wilms tumor whose serum alpha-fetoprotein level was elevated. To our knowledge, this extremely rare type of case is reported for the first time in the literature.