Age-related changes in the cat testis and epididymis.

Forty-two pairs of testes and epididymides were obtained from clinically healthy cats and were examined histologically for age-related changes. All of the following testicular features increased with age: thickness of the testicular tunica adventitia, the amount of lipofuscin in the interstitial cell, hyperplasia of interstitial cells, vacuolation of Sertoli cell cytoplasm, degeneration of seminiferous tubules and thickness of the seminiferous tubular basement membrane. Two spermatoceles were found in the oldest cat. Age-related changes in the cat epididymis included increased thickness of the epididymal tunica adventitia, occasional intraepithelial cysts and hyperplasia of the epithelium, and one spermatocele in the head of the epididymal duct. Lymphocytic foci were common in testicular and epididymal connective tissue of cats of all ages and were reactive in the 2 oldest cats. Several changes were most frequent in 3- to 6.9-year-old cats: eosinophilic to amphophilic round cytoplasmic bodies in interstitial cells, proteinaceous tubular luminal debris, and spermatozoa in the epididymal duct. Cats less than 1 year old had significant (P less than 0.05) amounts of seminiferous tubular degeneration and a high percentage of epididymal intraepithelial cysts and hyperplasia.