Cerebrospinal fluid cytology: diagnostic accuracy and comparison of different techniques

Cytologic examination of cerebrospinal fluid was performed in 1,021 patients, using Nuclepore and Millipore filter techniques. Positive findings were obtained in 89 cases, including 40 with primary central nervous system tumors, 24 with metastatic tumors and 25 with leukemic or lymphomatous involvement. When correlated with histologic findings, the overall detection rate was 32.2 per cent for primary tumors, 53.3 per cent for metastatic tumors and 65.8 per cent for leukemia and lymphoma. Highest degree of accuracy in the primary tumor group was achieved with medulloblastoma (61.9 per cent). Among metastatic tumors, those originating in the lung (70 per cent) and breast (83 per cent) were the one most often detected. Comparison of the two filter techniques indicated a slightly higher detection rate when the Millipore filter was used. The reasons for this are not entirely clear, but increased cellular yield with the Millipore filter may be an important factor. The cytocentrifuge method was found to be generally inferior to either of the filter techniques in quality of cell preservation. Our findings indicate that diagnostic usefulness of cerebrospinal cytology depends on collection and preparation methods as well as the anatomic distribution and biologic behavior of the lesions.