Adenomatous hyperplasia of the rete testis. A review and report of new cases.

Adenomatous hyperplasia of the rete testis (AHRT) is an uncommon benign lesion that preferentially involves the septal rete testis and mediastinal rete testis. It is usually an incidental finding in surgical specimens from cryptorchidism and testicular tumour. It can be found in autopsy specimens from patients dying with different chronic diseases and newborns with kidney diseases. Since its first description many articles have been published communicating new cases and putting forward some hypotheses on its aetiology and pathogenic mechanisms. Some authors suggest a role for hormonal changes, tumour invasion and action of chemical agents. We think that AHRT should be categorised into two main aetiological categories: congenital and acquired. The cases associated with different kidney and spermatic duct diseases, most cases associated with cryptorchidic testis and some cases associated with testicular germ cell tumour should be included in the congenital group. The remaining cases associated with chemical agents, some hormonal changes (i.e. androgen blockade) and most of the germ cell tumour cases can be considered as acquired AHRT. Differential diagnosis must be established mainly with metastatic adenocarcinoma of prostate to testis and primary adenocarcinoma of the rete testis. Pseudohyperplasia of the rete testis must also be considered in atrophic testes. Here we review the papers published on this subject and report our recent cases.