Incidence and structure of the appendices of the testis and epididymis

In paired tests obtained from 425 adults, 50 children and 10 neonates, the incidence of testicular appendices was 76% in adults (93.3% sessile) and 83.3% in neonates/children (88% sessile). An epididymal appendix was present in 21.9% of adults and 20% of neonates/children, out of which 79% were stalked in both types of specimen. Three sessile testicular appendices and 11 epididymal appendices were double. The microscopic structure of the appendices and the ultrastructure of their epithelia are described. Testicular or epididymal appendices were not present in any domestic or laboratory animal examined except the horse.