A Rare Testicular Serous Cystadenocarcinoma Diagnosed in a Retroperitoneal Lymph Node Dissection Specimen With a Review of the Literature.

Ovarian-type epithelial tumors of the testicular and paratesticular tissue are rare tumors that histologically resemble their ovarian counterparts. These tumors pose significant diagnostic challenges, especially to general pathologists, and may be misdiagnosed as the more commonly encountered germ cell tumors or mesotheliomas, if an appropriate immunohistochemistry panel is not applied. In this case report, we describe a serous cystadenocarcinoma in the retroperitoneal lymph node dissection specimen which was initially misdiagnosed in the primary testicular tumor as a germ cell tumor at an outside center, thus emphasizing the role of the pathologist in critically evaluating the histomorphological findings and applying a comprehensive immunohistochemistry panel to argue against the differential diagnoses at this site and reach the correct diagnosis.