Unilateral Cervical and Segmental Uterine Horn Aplasia With Endometrial Hyperplasia, Mucometra, and Endometritis in a Domestic Rabbit (Oryctolagus cuniculus)

An adult female rabbit was presented for routine ovariohysterectomy. The preanesthetic evaluation was unremarkable. During surgery, it was noted that the right uterine horn was distended and discontinuous with the vagina owing to the absence of the right cervix. The left uterine horn was enlarged and both ovaries appeared normal. The ovariohysterectomy was performed, and the reproductive tract was submitted for histopathology. The rabbit recovered uneventfully from surgery and was still doing well 6 months after surgery. A diagnosis of cervical and segmental uterine aplasia with mucometra was made in the right uterine horn, with endometrial hyperplasia and mild endometritis present in both uterine horns. Segmental uterine aplasia is a rare developmental disorder resulting from a defect in the formation of paramesonephric ducts during embryological development. Segmental uterine aplasia can be an incidental finding at presentation, as is in this case. However, associated complications and concurrent developmental defects can result in overt clinical signs.