Etiology of prune belly syndrome: evidence of megalocystic origin in an early fetus.

Background: Prune belly syndrome is a rare and complicated condition affecting the genitourinary organs and abdominal wall. The etiology of abdominal musculature deficiency in prune belly syndrome is controversial. We present a case that should elucidate the etiology of this syndrome.

Methods: A spontaneously aborted fetus at 12 weeks' gestation with an early stage of prune belly syndrome was investigated by necropsy and light and electron microscopy. Megalocystis resulting from urethral atresia was diagnosed. There was no hydroureter or hydronephrosis, and both light and electron microscopy demonstrated evidence of development of the abdominal musculature. Both testes were elevated as a result of the megalocystis.

Conclusions: These findings suggest that hypoplasia of the abdominal musculature and cryptorchidism might develop secondary to the presence of chronic megalocystis in this syndrome.