INTRODUCTION AND IMPORTANCE: Bladder cancer is predominantly characterized by urothelial carcinomas, but small cell neuroendocrine carcinomas (SCNEC) represent a rare and aggressive subset. CASE PRESENTATION: A 50-year-old male presented with painless hematuria and voiding difficulties. Ultrasonography revealed a 3.2 × 3 × 1.8 cm lesion with irregular margins and microcalcifications in the bladder. Computed tomography urography suggested an intra-vesical protruding mass. The patient underwent transurethral resection of the bladder tumor (TURBT). Histopathological examination confirmed SCNEC and papillary urothelial neoplasm of low malignant potential (PUNLMP), with high Ki-67 (90 %). PET-CT ruled out metastasis. Treatment included chemotherapy followed by radiotherapy. CLINICAL DISCUSSION: At one-year follow-up, the patient was undergoing radiotherapy after completing chemotherapy. This case highlights the importance of multimodal treatment for aggressive bladder cancers, emphasizing TURBT, adjuvant chemotherapy, and radiotherapy. CONCLUSION: Comprehensive management, including chemotherapy and radiotherapy, is critical in treating rare and aggressive bladder cancers like SCNEC, leading to improved outcomes.