腎盂原發性神經內分泌癌：罕見疾病之診斷陷阱

楊欣庭  王彥傑

國泰綜合醫院 外科部 泌尿科

Primary Neuroendocrine Carcinoma of the Renal Pelvis: Diagnostic Pitfalls in a Rare Entity

Hsin-Ting Yang, Yen-Chieh Wang

Division of Urology, Department of Surgery, Cathay General Hospital, Taipei, Taiwan

Abstract

Primary renal neuroendocrine carcinoma (NEC) is exceedingly rare, particularly when arising from the renal pelvis. We report an 84-year-old Taiwanese woman who presented with a three-month history of intermittent painless gross hematuria. Imaging studies revealed a 4cm lobulated mass within the right renal pelvis without lymphadenopathy. Ureterorenoscopy was unsuccessful due to ureteral stricture, and urine cytology was inconclusive. Given the clinical suspicion of upper tract urothelial carcinoma, robotic-assisted nephroureterectomy with bladder cuff excision was performed.   

Histopathological examination demonstrated a poorly differentiated carcinoma with neuroendocrine features, and immunohistochemistry showed diffuse synaptophysin positivity, confirming neuroendocrine carcinoma. No other primary lesion was identified. The patient had an uneventful postoperative course and received adjuvant radiotherapy. At two-year follow-up, no evidence of recurrence was observed.

Renal pelvic NEC often mimics urothelial carcinoma clinically and radiologically, making preoperative diagnosis challenging. Definitive diagnosis relies on histopathology and immunohistochemical staining. Although treatment strategies are not well established, radical nephroureterectomy with consideration of adjuvant therapy remains the mainstay for localized disease.

This case highlights the importance of including NEC in the differential diagnosis of renal pelvic tumors and demonstrates that favorable outcomes can be achieved with complete surgical resection and individualized adjuvant treatment.