Unilateral hyperplasia of the oviduct in a dog with a history of normal reproduction

A 2.5-year-old mixed-breed female dog with a history of normal reproduction underwent ovariohysterectomy. A large, asymmetrical, reddish mass about 12.5 × 9 cm was discovered between the uterus and left ovary in the location of the left oviduct. No abdominal free fluid was detected, and the surrounding tissues and organs appeared normal in size and position. The histopathological examination of the tissue section revealed significant multifocal stratification of the fallopian tube (FT) epithelial cell lining, along with nuclear crowding. Additionally, mild chronic lymphocytic salpingitis, as well as edema and congestion, were observed. There was no evidence of atypia, mitotic activity, or invasion of the tubal wall. In conclusion, hyperplasia of oviducts is a rare case and can occur without clinical signs related to fertility in the dog.