Very late extragonadal recurrence of testicular seminoma presenting as a bladder mass: a case report.

Very late relapse of testicular seminoma is rare and typically occurs at conventional metastatic sites such as the retroperitoneum, mediastinum, or lungs. Extragonadal recurrence involving the urinary bladder is particularly uncommon and may pose diagnostic challenges. We report the case of a 52-year-old male who presented with painless visible hematuria 16 years after undergoing radical inguinal orchidectomy for stage I testicular seminoma. Imaging revealed a large infiltrative mass arising from the left posterolateral wall of the urinary bladder, with extension into the prostate and distal ureter, resulting in severe hydronephrosis. Serum tumor markers, including alpha-fetoprotein, beta-human chorionic gonadotropin, and lactate dehydrogenase, remained within normal limits. Transurethral resection of the bladder tumor was performed, and histopathological examination, supported by immunohistochemistry, demonstrated features consistent with classical seminoma. The disease was characterized as locally advanced, with regional lymph node involvement and no evidence of distant metastases. Multidisciplinary management was initiated, including systemic platinum-based chemotherapy and urinary decompression. This case illustrates that seminoma may rarely recur after prolonged disease-free intervals and at atypical anatomical sites, with findings supporting late metastatic recurrence rather than a primary extragonadal germ cell tumor. It also emphasizes that normal tumor marker levels do not exclude recurrence and that histopathological confirmation remains essential for accurate diagnosis. Recognition of unusual presentations in long-term survivors of germ cell tumors is important to facilitate timely diagnosis and appropriate management.