Abstract
Introduction: Neuroendocrine/small-cell prostate cancer (NEPC) is a rare and aggressive subtype of prostate cancer, which typically develops after prolonged treatment for metastatic castration-resistant disease, but can, less commonly, occur de novo. Case Presentation: We describe a case of de novo NEPC in a tumor with mixed pathology including acinar adenocarcinoma and neuroendocrine/small-cell carcinoma with rapid progression of metastatic disease. Despite initiation of treatment with androgen deprivation therapy (ADT) and chemotherapy, the patient continued to exhibit progression leading to multiple complications including a large bowel obstruction and ultimately progressive hepatic metastases resulting in liver failure. Conclusion: This case illustrates the clinical presentation and highly aggressive nature of de novo NEPC. Recognizing atypical clinical progression in prostate cancer is critical for the detection of NEPC; however, despite early identification and initiation of treatment, the prognosis remains poor, thus highlighting the need for further study into NEPC biology and novel therapeutic approaches.