it is incidentally found in autopsy specimens and surgical specimens with cryptorchidism and testicular germ cell tumor . this non - neoplastic lesion is usually seated in the mediastinum and septal part of the rete testis . it may present as a very small lesion detected in microscopic examination or a solid - cystic mass lesion which is macroscopically evident . in microscopic evaluation cryptorchidism was unilateral and the other testis was normal . there were no clinical or endocrine abnormalities . the testis measured 4  2.5  2.2 cm in size and there was no tumoral lesion in gross examination . on the cut section close to the testis parenchyma , there was a gland like tubular structures . some of these were in back - to - back position with little intervening stroma . the testicular parenchyma was comprised of seminiferous tubules that had sertoli cells only and no spermatozoa ( fig . ema ( novocastra ; 1/150 , clone gp 1.4 , newcastle , united kingdom ) and pankeratin ( novocastra ; 1/150 , clone ae1/ae3 , newcastle , united kingdom ) immunohistochemical stains were performed for diagnosis . adenomatous hyperplasia of the rete testis is a benign lesion which can appear at any time during life and was first described by nistal et al . 
 . it is important to recognize tumor - like lesions of the rete testis to make an accurate differential diagnosis whether the lesion is benign or malign . ahrt etiology is not well understood yet but there seem to be associated conditions such as cryptorchidism , some kidney diseases , and germ cell tumors . our case was cryptorchid and seminiferous tubules near the lesion were lined by only sertoli cells and had no spermatozoa . the authors reported an adult case with ahrt in unilateral testis with no luminal spermatozoa . there are different cases such as prostate adenocarcinoma or embryonal carcinoma together with ahrt in the literature [ 6 , 7 ] . the true epithelial proliferation with gland - like or papillary proliferations replacing normal epithelium , continuous architecture of normal rete testis with adenomatous hyperplasia and lack of signs of malignancy are the proper diagnostic criteria for ahrt . in our case the differential diagnosis should include adenoma , papillary adenoma , primary and metastatic adenocarcinoma and rete testis cystic transformations with epithelial metaplasia . clinical history , localization , histologic features and immunohistochemistry are criteria for differentiating these lesions . complete surgical resection is the proposed therapy for ahrt cases and no report for recurrence has been identified . in conclusion , adenomatous hyperplasia of the rete testis is a rare lesion that can be confused with malignancy and should be remembered in the differential diagnosis of rete testis lesions .