Congenital mesoblastic nephroma rich from mitosis after in vitro fertilization: a case report.

Recently, various childhood tumors such as leukemia, neuroblastoma, hepatoblastoma, retinoblastoma, and central nervous system tumors in patients born after assisted conception have been reported. Although involvement of in vitro fertilization in the tumor pathogenesis was not established, the likely effect of assisted reproductive technology has been increasingly considered in these tumors in the last decade. Congenital mesoblastic nephroma is the most common renal tumor of infancy younger than 6 months associated with an overall good prognosis. The cellular variant of congenital mesoblastic nephroma, which occurs primarily in infants older than 3 months, confers a less favorable prognosis. We present a case of an atypical congenital mesoblastic nephroma with cellular elements in a 2-month-old infant who was born after in vitro fertilization. To our knowledge, this is the second congenital mesoblastic nephroma case and the first one with cellular variant reported to date in the English literature after a pregnancy induced by an assisted reproductive technology.