We present the case of a 70-year-old man who had a prostate adenocarcinoma that metastatized to a previously unknown cranial meningioma. Central nervous system (CNS) metastases are very uncommon in patients with prostate cancer, and metastases to pre-existing primary CNS tumours are even more uncommon. Rare events like this can cause diagnostic uncertainty, as shown by this case. This case is a reminder for clinicians to consider prostate metastases in patients with known prostate carcinoma and focal neurological symptoms.