Primary small-cell neuroendocrine carcinoma of the bladder: Case report and literature review

Background: Neuroendocrine tumours (NET) are extremely rare and aggressive. Although they commonly affect intestine, many organs may be involved such as pancreas, lung or urinary tract. Bladder is rarely involved. Actually, two main forms of bladder NET have been described: small-cell and large-cell. The first one is considered highly agressive since it shows poor oncologic outcomes being mainly diagnosed at advanced stage: the second one is extremely rare and equally aggressive.
Case report: A 78-years-old Caucasian male presented to our facility for lower urinary tract symptoms and gross hematuria recently occurred. He was a strong smoker since many years. No familiarity for urothelial cancer was referred nor previous episodes of hematuria until that time. Citology was negative; outpatient ultrasound of the bladder revealed a 3 cm bladder thickening highly suspicious for bladder cancer; patient underwent TC scan that confirmed the bladder lesion. A transurethral resection of the bladder (TURB) was performed. After 3 months total body TC showed multiple visceral metastases also involving brain and lymph nodes. Best supportive care was offered but the patient died 6 months later.
Results: Pathology revealed a mixed bladder tumor: 30% of the specimen resulted as an high-grade urothelial cancer (G3) and 70% as small-cell neuroendocrine variant.Microscopic muscle involvement was excluded.
Conclusions: Neuroendocrine tumors are uncommon entities which origin from cells of neuro-endocrine system and may potentially involve all human tissues. Neuroendocrine smallcell carcinoma of the bladder is a non-urothelial histotype: it is highly aggressive and diagnosed mainly at advanced stages. Whenever considering the high risk of metastatic spread and the poor prognosis, a multimodal approach is highly suggested. TURB alone is uneffective in disease control due to its aggressive nature. Unless metastatic, radical cystectomy and adjuvant chemotherapy represent the gold standard.