Cerebrospinal fluid cytological and biochemical characteristics in the presence of CNS neoplasia.

Central nervous system (CNS) infiltration must be ruled out in patients with known neoplastic diseases and neurological symptoms. It was done a retrospective analysis of 1,948 CSF samples from patients with suspected malignant infiltration in the CNS, in order to evaluate the positivity rate of malignant cells in cerebrospinal fluid (CSF) samples and correlate with cytochemical characteristics. Sixty-two percent of subjects had acute lymphocytic leukemia. Malignant cells were found in 24% of all CSF samples. Subjects with positive malignant cells had predominance of increased levels of CSF total protein (TP), glucose and total cytology (p<0.05). Mean total cell count in this group was 232 (SD 933) cells/mm(3), compared to 9 (SD 93) cells/mm(3) in the group without neoplasic cells (p=0.029). CSF TP specificity was 87% and negative predictive value (NPV) 96%. CSF total cell count specificity 86% and NPV 97%. Although sensitivity and positive predictive value were low. The presence of inflammatory cells and elevated TP found in patients with malignant cells in the CSF can aid in diagnosing CNS neoplasms.