CSF and clinical data are useful in differentiating CNS inflammatory demyelinating disease from CNS lymphoma.

Background: It is often difficult to diagnose central nervous system (CNS) inflammatory demyelinating diseases (IDDs) because they are similar to CNS lymphoma and glioma.
Objective: To evaluate whether cerebrospinal fluid (CSF) analysis can differentiate CNS IDDs from CNS lymphoma and glioma.
Methods: We measured CSF cell counts; concentrations of proteins, glucose, interleukin (IL)-6, IL-10, soluble IL-2 receptor (sIL-2R), and myelin basic protein; and IgG index in patients with multiple sclerosis (MS, n = 64), neuromyelitis optica spectrum disorder (NMOSD, n = 35), tumefactive demyelinating lesion (TDL, n = 17), CNS lymphoma ( n = 12), or glioma ( n = 10). We detected diagnostic markers using logistic regression and receiver operating characteristic (ROC) analyses.
Results: Median CSF IL-10 and sIL-2R levels were higher in CNS lymphoma patients than in MS, NMOSD, or TDL patients. Logistic regression revealed that CSF sIL-2R levels predicted CNS lymphoma. In the ROC analysis of CSF sIL-2R levels, the area under the curve was 0.867, and the sensitivity and specificity were 83.3% and 90.0%, respectively.
Conclusion: CSF sIL-2R levels can be used to differentiate CNS lymphoma from CNS IDDs. Further studies may identify other applications of CSF as a diagnostic biomarker.