Anatomical relationships between testis and epididymis during the fetal period in humans (10-36 weeks postconception)

To determine the anatomy of the epididymis and its relationship with the testis during the fetal period in normal individuals.

We studied bilaterally 146 testes and epididymides taken from 73 normal fresh human fetuses ranging in age from 10 to 36 weeks postconception. The epididymal anatomy was classified in six types: type I: the epididymis is connected to the testis by its head and tail and the epididymal body is separated from the testis; type II: the epididymis is completely attached to the testis; type III: the epididymis is attached to the testis only by its head; type IV: the epididymis is attached to the testis only by its tail; type V: the epididymis is completely detached from the testis; type VI: segmental atresia of the epididymis.

Normal epididymal anatomy, considered type I and type II, was found in 89.72% and in 7.53% of the cases, respectively. Type III and type IV epididymal anatomy was found in only 2.05% and 0.68% of the cases, respectively. We did not find types V and VI epididymal abnormalities.

Our results show that irrespective of testicular position during the fetal period, the incidence of epididymal abnormalities in normal fetuses is very low (2.75%) when compared with previous reports in patients with cryptorchidism and/or with a patent processus vaginalis (36-79%).