Background: Small-cell neuroendocrine carcinoma of the prostate (SCPC) is a rare and aggressive malignancy, accounting for less than 2% of prostate cancers. It is typically characterized by low prostate-specific antigen (PSA) levels, rapid progression, and poor response to hormonal therapy. Case Presentation: We report the case of a 71-year-old male with multiple comorbidities, who presented with lower urinary tract symptoms. Imaging revealed a large pelvic mass, extensive lymphadenopathy, and innumerable pulmonary nodules, while PSA was 1.4 ng/ml. Pathology review confirmed small-cell neuroendocrine carcinoma of the prostate (SCPC). The patient underwent systemic chemotherapy with six cycles of carboplatin and etoposide, achieving an eight-month disease-free interval. Surveillance imaging revealed significant locoregional progression with recurrent hydronephrosis, retroperitoneal lymphadenopathy and new liver metastases. Immediate rechallenge with carboplatin and etoposide. Conclusion: This case highlights the aggressive course of small-cell carcinoma of the prostate, characterized by atypical PSA kinetics, early visceral metastasis, and rapid progression despite systemic therapy.