Unilateral hydrosalpinx and absence of the infundibulum in a mare

Both ovaries and associated oviducts were removed from a mare via colpotomy. The right oviduct was greatly enlarged and filled with fluid. No infundibulum could be identified; rather, the blind distended end of the oviduct adhered to the ovary at the ovulation fossa. Two cysts were attached to the exterior of the oviduct a few centimeters from the fossa. Histologic examination of the oviduct and cysts revealed a dilated lumen, a decreased infolding of the wall into the lumen, and a lack of a defined muscle layer. Congenital absence of the infundibulum resulting in a blind ampullar terminus is proposed as the cause of the hydrosalpinx.