[Metastasis involving the leptomeninges and ventricles of the brain--CT evaluation]

The diagnosis of leptomeningeal or ventricular metastasis by cranial computerized tomography (CT) contributes to earlier treatment and sometimes alters the management of patients with intra- or extra-cranial malignancy. In 20 cases whose metastasis were spreaded via CSF seeding, the abnormal CT findings were 1) mass or nodule in the ventricles or subarachnoid space, 2) ependymal, subependymal enhancement, 3) sulcal, gyral or cisternal enhancement, 4) hydrocephalus not related to the obstruction of primary tumor, 5) falx or tentorial enhancement. In another 8 cases, the metastasis developed through hematogeneous spreading to the choroid plexus or paraventricular parenchyma. The mass or nodule within the ventricles could be well identified with enhanced CT scan. The involved ventricles, in order of frequency, were lateral, 3rd, and 4th ventricles in our series.