Detection of DNA abnormalities by flow cytometry in cells from cerebrospinal fluid

To evaluate the diagnostic utility of flow cytometry (FCM) as compared to cytology, DNA and RNA content of cells were measured in 233 samples of cerebrospinal fluid (CSF) from 147 patients with solid tumors or lymphomas and 17 controls with nonmalignant disorders. All control specimens were normal. Twenty-eight samples were abnormal: 20 showed an aneuploid peak and 8 an increased number of cells with DNA content in the S and G2M phases of the cell cycle. Of these 28, cytologic results were positive in 18, suspicious in 3, and negative in 7. All but one of the suspicious and negative cases had confirmatory laboratory and/or radiographic evidence of leptomeningeal metastasis within one week of FCM examination. Cytologic results were positive in eight samples negative by FCM. Compared with cytology, the sensitivity of FCM was 69% and the specificity 95%. Abnormal DNA content by FCM can be a useful adjunct to cytologic examination.