Neoplastic meningitis: A study from a Tertiary Care Hospital from coastal India

Introduction: Neoplastic involvement of cerebrospinal fluid (CSF) secondary to known or unknown primaries elsewhere is a poor prognostic factor and is equivalent to stage IV disease. Aim: The aim of the study is to analyse the cytological features of neoplastic meningitis in a tertiary care center. Materials and Methods: A retrospective study of 400 consecutive CSF samples was done in the cytology laboratory of our hospital. The fluid obtained by spinal tap was sent for microbiological, biochemical and cytological evaluation. Smears that showed the presence of malignant cells were included in this study. Results: Out of 400 cases, 36 (9%) showed neoplastic meningitis. Of which, 13 cases (36%) revealed leukemic infiltration, 2 (6%) lymphomatous infiltration and 21 (58%) carcinomatous meningitis. The leukemia cases included seven cases of acute lymphoblastic leukemia and six cases of acute myeloid leukemia. Among the carcinomatous meningitis cases, eight were metastasis from carcinoma breast, six from lung carcinoma and one each from malignancies of gallbladder, stomach and retinoblastoma. Four cases were metastatic adenocarcinoma from unknown primary. Pleocytosis was a significant finding seen in 58% cases (n = 21). Elevated protein and hypoglychorrhachia was noted in 68% cases (n = 18). Conclusion: A combined diagnostic approach including biochemical, microbiological and pathological evaluation was useful in eliminating infectious meningitis and confirming neoplastic meningitis in these cases. Cytology should be performed on cerebrospinal specimens from all patients with known or suspected malignancy with meningismus. Detection of malignant cells on cytological examination of CSF is the diagnostic gold standard for neoplastic meningitis.