以疑似婦科惡性腫瘤為臨床表現之原發性尿道腺癌：在診斷困難情況下的決策

陳浩恩^1,3, 陳進利^2,3

¹國軍臺中總醫院 外科部 泌尿外科, ²三軍總醫院 外科部 泌尿外科, ³國防醫學大學

Primary urethral adenocarcinoma presenting as a gynecologic malignancy: decisions in the setting of diagnostic challenges

Hao-En Chen^1,3, Chin-Li Chen^2,3

¹ Division of Urology, Department of Surgery, Taichung Armed Forces General Hospital, Taichung, Taiwan

² Division of Urology, Department of Surgery, Tri-Service General Hospital, Taipei, Taiwan

³ National Defense Medical University, Taipei, Taiwan

Introduction:

Primary urethral adenocarcinoma in women is an extremely rare malignancy that often presents with non-specific lower urinary tract symptoms, leading to delayed diagnosis. Its submucosal and extraluminal growth, frequently involving the periurethral tissue and anterior vaginal wall, can closely mimic gynecologic malignancies on imaging. In addition, early cystoscopic findings are often non-diagnostic. Accurate identification of the primary origin therefore relies on integrating immunohistochemical analysis, anatomical tumor distribution, and surgical pathology.

Case presentation:

A 56-year-old woman presented with progressive pelvic discomfort, dysuria, anterior vaginal wall pain, and voiding difficulty for 6 months. Imaging revealed bilateral hydronephrosis, cervical prominence, and a periurethral lesion involving the vagina, initially suggesting gynecologic malignancy. Vaginal biopsy showed poorly differentiated adenocarcinoma with CK20 and CDX-2 positivity and focal CK7 expression, indicating intestinal differentiation and a non-gynecologic origin. Cystoscopy demonstrated urethral narrowing without a discrete tumor, and gastrointestinal endoscopy showed no primary lesion. Transurethral biopsy confirmed urethral adenocarcinoma, although the primary site remained uncertain. The patient received cisplatin-based concurrent chemoradiotherapy, followed by anterior pelvic exenteration with ileal conduit urinary diversion and lymph node dissection. Final pathology confirmed primary urethral adenocarcinoma with invasion of the bladder, cervix, and vagina, and pelvic lymph node metastases (pT4N2M0).

Conclusion:

Female urethral adenocarcinoma may mimic gynecologic malignancies and evade early cystoscopic detection. Negative or non-specific cystoscopic findings do not exclude aggressive periurethral tumors. In diagnostically uncertain cases, correlating immunohistochemical findings with tumor spread is more reliable than imaging alone for identifying the primary origin. Treatment should be guided by oncologic adequacy rather than presumed primary site to achieve optimal disease control.