Primary Pure Yolk Sac Tumor of the Urinary Bladder: A Case Report

Introduction Yolk sac tumors are malignant germ cell tumors that typically arise in the gonads. Although extragonadal cases have been reported, primary involvement of the urinary tract is extremely rare. Case Presentation A 67‐year‐old man presented with gross hematuria. Cystoscopy and contrast‐enhanced computed tomography revealed a 6‐cm bladder mass. Transurethral resection of the bladder tumor was performed. Histopathological and immunohistochemical findings (alpha‐fetoprotein, glypican‐3, and Sal‐like protein 4 positivity) were consistent with a yolk sac tumor without a urothelial carcinoma component. Additional examinations revealed no primary lesions elsewhere, leading to the diagnosis of a primary bladder yolk sac tumor. The patient received four cycles of etoposide and cisplatin chemotherapy and has remained recurrence‐free for 2 years. Conclusions Patients with primary bladder yolk sac tumors, although rare, may achieve favorable outcomes with combined surgical resection and chemotherapy.