膀胱癌小細胞型神經內分泌腫瘤：病例報告

李琇碧、江怡德

衛生福利部雙和醫院 泌尿科

Small Cell Neuroendocrine Carcinoma of the Bladder: A Case Report

Siou-bi Li, Yi-Te Chiang 

Department of Urology, Shuang Ho hospital, Taipei Medical University, Taipei, Taiwan

Introduction: 

Small cell neuroendocrine carcinoma (SCNC) of the bladder is a rare and aggressive malignancy, representing 0.5–2% of all bladder cancers. SCNC typically presents at an advanced stage with poor prognosis and high metastatic potential. This report presents a case of high-grade SCNC in a 57-year-old male, who received neoadjuvant chemotherapy and following operation. 

Case Description: 

A 57-year-old male with a history of chronic hepatitis B initially presented to the outpatient department with micturition pain for six months, accompanied with hematuria and dysuria. After excluding urolithiasis, further computed tomography urography revealed a 2.7 cm soft tissue mass at bladder near right ureterovesical junction causing proximal hydroureteronephrosis, highly suspicious for urothelial carcinoma. Cystoscopy identified a large papillary tumor originating from the right ureteral orifice. Transurethral resection of the bladder tumor (TURBT) and biopsy by right ureteroscopy (URS) were performed, and pathology confirmed high-grade small cell carcinoma invading the muscularis propria. Given the aggressive nature of the tumor, the patient was referred for neoadjuvant chemotherapy (etoposide and cisplatin) for four cycles. However follow-up computed tomography showed tumor progression with enlarged size and suspicion of invasion into the right prostate gland. After neoadjuvant chemotherapy, radical robotic-assisted cystectomy with standard pelvic lymph node dissection and U-shaped extracorporeal ileal neobladder reconstruction was performed. Pathology revealed high-grade small cell neuroendocrine carcinoma invading perivesical tissue, prostate, and seminal vesicles, with positivity for neuroendocrine markers (INSM1, synaptophysin) and a high Ki-67 proliferation index (>80%). Bilateral external iliac, internal iliac and obturator lymph nodes (a total of 20 lymph nodes) reported no metastasis, thus the stage of cancer corresponded to pStage IIIA T4aN0. A concurrent acinar adenocarcinoma of the prostate (Gleason 4+3=7) was also identified.

Discussion:

Bladder small cell neuroendocrine carcinoma is rare and generally associated with an aggressive clinical course, frequently presenting at advanced stages with a high risk of metastasis. Based on previous case reports and observational studies, treatment of bladder small cell neuroendocrine carcinoma was primarily extrapolated from the literature reporting small cell lung carcinoma. For localized disease, treatment typically includes concurrent chemoradiotherapy or neoadjuvant chemotherapy (platinum-based regimen plus etoposide) followed by either radiation or cystectomy; for metastatic disease, cytotoxic chemotherapy (usually cisplatin or carboplatin) is recommended. Though our patient responded poorly to neoadjuvant chemotherapy with tumor progression shown by follow-up image, there was no distant metastasis found during staging. Surgical intervention remains a critical part of management for locally advanced disease without metastasis. This case indicates the necessity of early recognition and aggressive treatment for small cell neuroendocrine carcinoma of the bladder. The favorable outcome following neoadjuvant chemotherapy and radical cystectomy highlights the importance of a multidisciplinary approach.

Conclusion:

This case demonstrates the aggressive nature of bladder small cell neuroendocrine carcinoma and the complexity of treatment. Early intervention with neoadjuvant chemotherapy and comprehensive surgical resection led to a favorable short-term outcome, underscoring the value of vigilant follow-up and personalized treatment strategies in managing such aggressive genitourinary cancers.