Neuroendocrine Transformation Without PSA Elevation in High-Risk Metastatic Castration-Sensitive Prostate Cancer Under Androgen Receptor Signaling Inhibition: A Case Report.

Abstract

Introduction: Neuroendocrine prostate cancer is a rare and highly aggressive variant of prostate cancer with a poor prognosis. We report a case in which metastatic castration-sensitive prostate cancer directly transformed into neuroendocrine prostate cancer without a corresponding increase in prostate-specific antigen.

Case presentation: An 86-year-old male with severe acute renal failure demonstrated a prostate-specific antigen level of 306 ng/mL and a Gleason score of 4 + 5 on prostate biopsy. Imaging revealed lung, bone, and lymph node metastases, leading to a diagnosis of high-risk metastatic castration-sensitive prostate cancer. Abiraterone acetate was initiated immediately. Nineteen months later, multiple liver metastases were detected despite stable prostate-specific antigen levels. The patient died 4 months later. Autopsy revealed widespread metastases, all histologically confirmed as neuroendocrine prostate cancer.

Conclusion: Strong androgen receptor suppression in metastatic castration-sensitive prostate cancer can lead to aggressive radiographic progression without prostate-specific antigen elevation, underscoring the limitations of antigen-based monitoring.