A 71-year-old man with a history of high-risk prostate adenocarcinoma (Gleason score 4 + 5 = 9) treated with brachytherapy in 2016 was referred for a Ga-prostate-specific membrane antigen (PSMA)-HBED-CC PET/CT scan for suspected cancer recurrence on a background of slowly rising serum prostate-specific antigen (0.95 ng/mL; reference, <0.2 ng/mL). This revealed PSMA-avid dura-based hyperdense lesions in the brain, suggestive of cerebral metastases. Biopsy demonstrated the presence of acid-fast bacilli, and with further clinical and microbiological testing, a diagnosis of PSMA-avid cerebral tuberculous mycobacterium infection was made.