Abdominal disseminated lesions following surgery for a testicular mucinous cystic neoplasm initially diagnosed as mucinous cystadenoma: a case report and literature review.

This report describes a rare testicular mucinous cystic neoplasm in a 78-year-old man who underwent scrotal exploration and right radical orchiectomy. Histopathology of the resected specimen was interpreted as an ovarian-type mucinous cystadenoma with focal epithelial proliferation. Six months after surgery, follow-up imaging demonstrated multiple abdominal and peritoneal lesions suspicious for disseminated disease. Because the abdominal lesions were diagnosed radiologically and were not histologically sampled, metastatic disease could not be pathologically confirmed. In addition, immunohistochemical analysis of the orchiectomy specimen was not performed, and a gastrointestinal primary tumor was not definitively excluded by endoscopic evaluation. The case highlights the diagnostic challenges of distinguishing benign, borderline, malignant, and metastatic mucinous tumors involving the testis, and it emphasizes the importance of postoperative surveillance, comprehensive clinicopathologic correlation, immunohistochemistry, and exclusion of an extratesticular primary site.