Bilateral Testicular Tumors Recurred 5 Years After Surgery for an Extragonadal Germ Cell Tumor: Case Report

Introduction: Extragonadal germ cell tumors (EGCT) account for approximately 3%-7% of all germ cell tumors. Metachronous testicular tumors develop in 5%-7% of patients after EGCT treatment; however, bilateral testicular tumors have not been reported. Case Presentation: A 30-year-old man underwent retroperitoneal tumor resection and was diagnosed as teratoma. A cystic lesion in the right testis without malignant features was managed by surveillance. Five years later, he presented with left testicular discomfort. Imaging revealed bilateral testicular tumors, and serum hCG was elevated (11.9 mIU/mL). Bilateral radical orchiectomy revealed pure seminoma (pT1) in the left testis and mixed germ cell tumor with seminoma and teratoma components (pT1) in the right testis. Conclusions: This is the first reported case of bilateral testicular tumors developing after EGCT treatment. In patients with EGCT, the potential presence of testicular germ cell neoplasia in situ should be considered, and long-term follow-up is recommended.