Abstract
A 9-year-old female dog was referred to Azabu University Veterinary Teaching Hospital for dysuria and dyschezia after ovariohysterectomy. After a series of diagnostic imaging, vaginal obstruction was suspected by vaginal fluid retention. Surgical repair was attempted three times to establish patency through the vagina and the vestibule by episiotomy and laparotomy. Another laparotomy was performed to remove the entire vaginal mucosal layer to prevent recurrence, which resulted in favorable outcome. Histopathological examination revealed that the resected tissue was a cyst originated from mesonephric duct remnant. In the present case, the cyst was curable by the entire resection of the cyst lining membrane, which could eradicate all the secretory cells with least damage to the urethral vasculature and innervation.