There are several tumor-like lesions and miscellaneous neoplasms of the rete testis. We present a case with adenomatous hyperplasia of the rete testis (AHRT). The patient was 24 years old with undescended testis and was referred to our hospital. There were no clinical or endocrine abnormalities. Cryptorchidism was unilateral and the other testis was normal. Right orchiectomy was performed and sent to the pathology laboratory for examination. Morphologic and immunohistochemistry findings confirmed the diagnosis of AHRT in the case. The patient's post-operative course continues uneventfully. AHRT is a rare lesion and can be confused with malignancy. It is incidentally detected in microscopic investigation. It may present as a very small lesion detected in microscopic examination or a solid cystic mass lesion which is macroscopically evident. Clinical history, localization, histology features and immunohistochemistry are criteria for differentiating these lesions.