[Three cases of metastatic meningeal carcinomatosis from lung cancer].

We report three cases of meningeal carcinomatosis that metastasized from lung cancer. The patients were men of 73, 65 and 77 years old. The histological type was adenocarcinoma in all cases. At the time of emergence of neurological symptoms such as nausea, headache and cataplexy, enhanced CT of the brain did not disclose brain metastasis. Although brain MRI failed to detect abnormal meningeal findings in cases 1 and 2, meningeal carcinomatosis was diagnosed by cerebrospinal fluid cytology in all three cases. As for treatment, in case 1, methotrexate and prednisolone were administered intrathecally, while the optimum supportive care was given in cases 2 and 3. Because it is difficult to detect meningeal carcinomatosis by brain CT and MRI alone, careful neurological observation and cerebrospinal fluid cytology are necessary for its diagnosis.