Hypoplastic testicles

Hypoplastic testicles secondary to abdominal retention in a 3-year-old Lusitan thoroughbred. Both gonads appear atrophied, with complete absence of epithelial germ cells on histological examination. Only Sertoli cells are present within the testicular tubules, which often exhibit intra-tubular calcification. The internal temperature of the abdominal cavity is higher than ideal for the production of sperm cells and retained testicles are rarely capable of producing spermatozoa.