Cranial nerve palsy caused by metastasis to the skull base in patients with castration‐resistant prostate cancer: Three case reports

INTRODUCTION: Skull base metastasis of prostate cancer associated with cranial nerve palsy is rare. We observed three patients with aggressive prostate cancer who experienced cranial nerve palsy. CASE PRESENTATION: Case 1 was a 53‐year‐old patient who was treated with carboplatin and etoposide. He noticed sensory abnormalities on his left mouth edge. Head magnetic resonance imaging revealed skull base metastasis. Case 2 was a 50‐year‐old patient who received docetaxel. This patient exhibited ptosis of the left eye. Skull base metastasis was detected by magnetic resonance imaging. External beam radiation therapy was performed. Case 3 was a 64‐year‐old patient who was treated with docetaxel. He experienced ptosis of the right eye and diplopia. He was also treated with external beam radiation therapy. CONCLUSION: External beam radiation therapy exhibited some efficacy against the symptoms, but skull base metastasis of treatment‐resistant prostate cancer has poor prognosis. Three patients died within 3 months after symptoms occurred with or without external beam radiation therapy.