Unilateral segmental aplasia of the epididymis and ductus deferens in a mixed-breed dog

Abstract

A 9-month-old male mixed-breed dog was presented for elective bilateral orchiectomy. During the procedure, segmental aplasia of the tail of the right epididymis and absence of the corresponding ductus deferens were observed. Additionally, the head of the epididymis on the affected side appeared enlarged. Histopathological examination revealed multiple sperm granulomas with inflammatory infiltrate composed of macrophages, multinucleated giant cells, neutrophils, lymphocytes, and plasma cells, as well as fibrosis. The epididymal tail and ductus deferens were absent. These gross and microscopic findings supported a diagnosis of segmental aplasia of the epididymis and ductus deferens.