Leptomeningeal carcinomatosis (a.k.a. carcinomatous meningitis or gliomatosis cerebri) can occur if metastatic cancers spread into the cerebrospinal fluid (CSF). This is typically seen at a later stage than when solid brain metastases arise from aggressive cancers.
Patients can have numerous types of symptoms including seizures, altered mental status, extremity weakness, numbness or pain. Diagnosis is made by a lumbar puncture confirming cancer cells. Patients can have mild to moderate hydrocephalus and need a ventriculoperitoneal shunt to help with their symptoms. This can also facilitate the administration of chemotherapy through the shunt into the circulating CSF. In the absence of hydrocephalus, a reservoir can be placed to allow for chemotherapy to be injected directly into the CSF.