Prostate Cancer - Double Vision but Solitary Lesion

A 53 year old man with a background of castrate-sensitive prostate cancer on intermittent androgen deprivation therapy (ADT) presented with right sixth nerve palsy secondary to a solitary right petroclival lesion involving adjacent dura and bone. The clinical and imaging characteristics of the lesion were consistent with a number of differential diagnoses (including metastatic prostate cancer, meningioma and chondrosarcoma). The patient initially declined biopsy and ADT was recommenced but the lesion continued to enlarge despite an excellent biochemical response. A subsequent biopsy of the petroclival mass demonstrated a WHO grade I meningioma and the patient proceeded to have definitive stereotactic radiotherapy. This case illustrates an unusual solitary skull base lesion in a man with prostate cancer. Whilst bony metastases, usually multiple, in the skeleton are common, solitary skull or brain lesions should be investigated as alternate diagnoses are likely in such circumstance.