Unexpected brain metastases from neuroendocrine prostate cancer detected by [¹⁸F]fluorocholine PET/CT: a case report

Neuroendocrine prostate cancer (NEPC) is a rare and aggressive variant of prostate carcinoma, often associated with atypical metastatic spread and poor prognosis. Brain metastases from NEPC are exceptional and may pose significant diagnostic challenges. We report the case of a 59-year-old man referred for initial staging of prostate cancer after a transrectal ultrasound-guided biopsy that initially demonstrated poorly differentiated adenocarcinoma. Whole-body [¹⁸F]fluorocholine positron emission tomography/computed tomography (PET/CT) revealed subcentimetric hypermetabolic foci in the left frontal and left temporal cortex and in the left cerebellar hemisphere, suggestive of brain metastases. Pelvic lymphadenopathy was also identified, with no evidence of bone or other visceral involvement. Subsequent histopathological re-evaluation of the initial biopsy, including extended immunohistochemical analysis, demonstrated a neuroendocrine (small cell) component. The patient underwent stereotactic radiotherapy for the cerebral lesions and localized radiotherapy for the primary prostatic tumor. This case underscores the diagnostic value of [¹⁸F]fluorocholine PET/CT in detecting unexpected metastatic sites in neuroendocrine prostate carcinoma. Early identification of central nervous system involvement may have therapeutic and prognostic implications, emphasizing the need for molecular imaging in atypical or aggressive prostate cancer phenotypes.