[Clinicopathological Features of Primary Small Cell Neuroendocrine Carcinoma of the Bladder]

Objective To investigate the clinicopathological features,immunohistochemical features,diagnosis,and relationship with sporadic prostate cancer in primary small cell neuroendocrine carcinoma of the bladder. Methods We retrospectively analyzed the clinical characteristics of 12 patients with primary small cell neuroendocrine carcinoma of the bladder diagnosed at Beijing Chao-Yang Hospital affiliated to Capital Medical University from January 2013 to September 2022.The histological features of primary small cell neuroendocrine carcinoma of the bladder were re-evaluated by two pathologists according to the 2022 revision of the World Health Organization Classification of Tumors of the Urinary System and Male Genital Organs.Electronic medical records were retrieved,and telephone follow-up was conducted from the time of histopathological diagnosis to the death or the end of the last follow-up until January 31,2023. Results The 12 patients include 7 patients in pT3 stage and 1 patient in pT4 stage.Eight patients were complicated with other types of tumors,such as high-grade urothelial carcinoma of the bladder and squamous cell carcinoma.Five patients had sporadic prostate cancer.Immunohistochemical staining showed that 12 (100.0%),10 (83.3%),and 8 (66.7%) patients were tested positive for CD56,Syn,and CgA,respectively.The Ki67 proliferation index ranged from 80% to 90%.Five patients with urothelial carcinoma were tested positive for CK20,GATA3,and CK7.P504S was positive in all the 5 patients with prostate cancer,while P63 and 34βE12 were negative.The follow-up of the 12 patients lasted for 3-60 months.Eight of these patients died during follow-up,with the median survival of 15.5 months.Four patients survived. Conclusions Primary small cell neuroendocrine carcinoma of the bladder is a rare urological tumor with high aggressiveness and poor prognosis.In male patients with bladder prostatectomy,all prostate tissue should be sampled.If prostate cancer is detected,the prostate-specific antigen level should be monitored.