Intradural spinal metastases in patients with posterior fossa brain metastases from various primary cancers.

Intradural spinal metastases (ISM) are rare and primarily found associated with certain types of brain tumors like medulloblastoma. Their association with metastases to the brain has been recently described and seems to occur more frequently in posterior fossa lesions. We reviewed patients treated at Massachusetts General Hospital for posterior fossa brain metastases from various primary cancers, and evaluated the risk of concomitant or subsequent ISM. Of 104 patients, 10 developed ISM, with a 1-year actuarial risk of 25%. The risk was not significantly related to age, sex, histology, site of primary tumor or previous therapy. The study suggests that in patients with posterior fossa metastasis, particular attention should be paid to seeding via cerebrospinal fluid and drop metastases to the spinal cord.