CT findings of seeding tumors

From 1981 to 1989 there were 43 from 154 cases of metastatic brain tumors, which seeded along the CSF pathways found in the Department of Radiology, Siriraj Hospital Medical School, Bangkok. These seeding tumors were spread from both primary intracranial (25 cases) and extracranial neoplasms (18 cases). Among the primary intracranial tumors, pineal neoplasm was the most frequent site (48%). The next rank was ependymoma (20%), medulloblastoma (16%), glioma (12%) and others (4%). The majority of extracranial neoplasms that seed in the CSF pathways were malignancy of lung (44.4%), choriocarcinoma (22%) and breast (11%). Lateral ventricle was the most frequent site of seeding (65%). The remaining tumors seeded in cisterns, leptomeninge and spinal subarachnoid space. CT is sensitive in detecting seeding tumors but not specific for each type of tumor.