Bladder Neuroendocrine Carcinoma: About Five Cases and Review of the Literature

Introduction: Primary neuroendocrine carcinoma of the bladder is an aggressive disease with significant metastatic potential. It is an extremely rare variation of non-urothelial carcinoma of the bladder, accounting for < 1% [1]. Given its rarity, no therapeutic consensus has been codified to date. We report a retrospective series of five cases and detail their anatomoclinical and therapeutic aspects. Patients and methods: This is a retrospective descriptive study of five cases of neuroendocrine carcinoma of the bladder collected at the Mohammed VI Center, between January 2017 and December 2020. The diagnosis was confirmed by immunohistochemical study. The median age is 61 years (extremes: 36-73 years), all patients are male. The average delay of consultation is 7 months (extremes: 2-12 months). Chronic smoking was found in three patients. Hematuria was the cardinal sign in 4 cases. Irritative urinary disorders such as pollakiuria and dysuria were noted in two cases. Cystoscopy showed a solid tumor in the majority of cases, located in the bladder trigone in two patients, and in the posterobasal wall in two others. Neuroendocrine carcinoma was pure in four cases and impure; associated with a poorly differentiated carcinoma component in only one case. The diagnosis of small cell neuroendocrine carcinoma of the bladder is retained after an immunohistochemical study. Chromogranin A was expressed in all cases and Synaptophysin in four cases. The extension work-up revealed locally advanced and immediately metastatic cancer in three patients (peritoneum, lung, skin). The performance status index was between 0 and 1. Palliative chemotherapy was recommended in three patients, two of whom refused all treatment. The other two patients received radiotherapy as adjuvant to neoadjuvant chemotherapy. Conclusion: The incidence of neuroendocrine carcinomas of the bladder is increasing due to the diagnostic progress by immunohistochemical means available today. They are often diagnosed at a stage that is already locally advanced or metastatic; their evolution is very rapid and their prognosis is poor. At the present time, there is no therapeutic consensus for their management.