Objective To investigate the clinicopathological features,diagnosis,treatment and prognosis of a case of large cell neuroendocrine carcinoma (LCNEC) in urinary bladder and ureter.Methods The clinical pathological data of a patient with LCNEC in urinary bladder and ureter was retrospectively analyzed and the related literatures were reviewed.It was a male patient,78 years old,presenting with total painless gross hematuria.The ultrasonography showed nodules on the left lateral wall of bladder.Cystoscopy showed 2 cm cauliflower-like mass on the left lateral wall of bladder,and pathologic biopsy showed bladder urothelial carcinoma.Results Transurethral resection of bladder tumor was performed.The tumor cells were large in size,with vesicular nuclei,prominent nucleoli and nested/trabecular architecture.Immunohistochemical analysis demonstrated that tumor cells were positive for synaptophysin,chromogranin A and CD56.The proliferation index evaluated with Ki-67 was about 80％.The pathology report revealed a large cell neuroendocrine bladder tumor with focal areas of high-grade urothelial carcinoma.After intravesical instillation therapy for 2 months,tumor recurrence was detected by CT.Laparoscopic radical cystectomy and ureteral segmental resection was performed.The pathology report revealed a LCNEC with focal areas of highgrade invasive urothelial carcinoma in the bladder and ureter.CT showed tumor recurrence with liver metastasis 1 month after the operation.The overall survival was 9 months.Conclusions The clinical and imaging findings of LCNEC in bladder and ureter are nonspecific.Diagnosis must depend on the pathological and immunohistochemical staining.The tumor is aggressive with high risk of recurrence and metastasis and has a poor prognosis.It is mainly treated with radical resection combined with chemotherapy.