A challenging discrimination of an intensely [F]PSMA-1007-avid solitary lesion at the skull base in a patient with biochemical recurrence of prostate cancer.

Prostate adenocarcinoma metastasis to brain has been reported to occur only up to 0.6% of patients and these are mostly diagnosed in autopsy series. In the setting of biochemical recurrence of prostate cancer, a suspected PSMA-avid (prostate-specific membrane antigen) lesion in the brain is still strongly suggestive of an intracranial metastasis of prostate cancer. This needs, however, a thoroughly recurrency work-up due to other potentially PSMA-avid cranial lesions, as PSMA initially was developed for the imaging of primary CNS tumours. We report of a challenging clinical case of a 71-year-old-patient with a strongly PSMA-avid lesion at the skull base. Given the medical history of a meningioma at the skull base, the further diagnostic work-up with MRI could still not rule out a malignancy, so that the patient needed to undergo a surgical excision of the tumour mass. The histological and immunohistochemical examinations revealed a relapsed CNS WHO grade 1 meningioma. From the aspect of molecular imaging and critical analysis of regular clinical care in a third-level university hospital, we consider this result very intriguing. Hence, we analyse the decision-making process and clinical course of this case in the light of molecular imaging findings.