Malignant idiopathic intracranial hypertension revealed a hidden primary spinal leptomeningeal medulloblastoma.

Frequently the cause of raised intracranial pressure remains unresolved and rarely is related to spinal tumours, moreover less to spinal medulloblastoma without primary brain focus. An 18-year-old woman had a 3-month history of headache and impaired vision. Neurological examination revealed bilateral sixth cranial nerve palsies with bilateral papilloedema of grade III. No focal brain or spine lesion was found on imaging. Consecutive lumbar punctures showed high opening pressure and subsequent increasing protein level. Meningeal biopsy was negative. At one point, she developed an increasing headache, vomiting and back pain. Spine MRI showed diffuse nodular leptomeningeal enhancement with the largest nodule at T6-T7. Malignant cells were detected in cerebrospinal fluid. She underwent laminectomy with excisional biopsy, and pathology showed medulloblastoma WHO grade IV. She was treated with chemotherapy and craniospinal irradiation and made a good recovery.