Cytodiagnosis of malignant lesions in cerebrospinal fluid. Review and cytohistologic correlation

In an evaluation of the efficacy of cerebrospinal fluid (CSF) examination in our laboratory, 1,635 CSF specimens received between March 1, 1975, and December 31, 1982, were reviewed. All 111 positive samples (from 77 cases) and all 141 suspicious samples (from 83 cases) were reviewed microscopically, and the clinical records in the cases were rechecked. The 77 positive cases were confirmed by tissue and other studies: 23 as primary brain tumors, 26 as secondary carcinomas, 14 as leukemias, 12 as lymphomas and 2 as multiple myelomas. The 83 suspicious cases were similarly confirmed: 31 as primary brain tumors, 14 as secondary carcinomas, 22 as leukemias and 7 as lymphomas-with 9 found to be "benign." There were no false positives in the positive group. This study suggests that the identification of malignant cells in CSF samples constitutes a reliable method of diagnosis and lessens the need for further biopsies.