There are two primitive tumors of the rete testis: adenomas with a benign behavior and adenocarcinomas with a malignant outcome. According to their architectural pattern, adenomas can be solid (sertoliform cystadenoma), papillary (papillary cystadenoma), cystic (cystadenoma), or with a fibromatous stromal component (adenofibromas). In addition to the most common variety, adenocarcinomas of the rete testis include clear cell adenocarcinomas. Two cases have been chosen as representative of this group: a sertoliform cystadenoma and an adenocarcinoma; they both make it possible to comment on the differential diagnosis not only between them but also with other tumors, as it is the case of adenocarcinoma, both primary tumors of the testis and metastases.

Case 98. Sertoliform Cystadenoma

Clinical case. An 18-year-old patient who incidentally discovered an intratesticular nodule. Serum levels of testicular tumor markers were negative.

Pathological findings. The orchiectomy specimen shows a 5-mm in diameter tumor located in the testicular mediastinum. The tumor consists of a nodular proliferation that grows preferentially inside the cavities of the rete testis. The cells are cylindrical and arranged to form cords, tubules, and acini. The nucleus is spherical or slightly elongated with longitudinal folds and a small nucleolus. The cytoplasm is broad and eosinophilic. Besides the intracavitary growth, nests of cells within a fibrous, and hyalinized stroma are observed in the proximal testicular parenchyma. There is continuity between the tumor and the epithelium of the rete testis. The tumor shows neither necrosis nor vascular infiltration. The testicular parenchyma has a normal spermatogenesis.