CSF interleukin 6 is a useful marker to distinguish pseudotumoral CNS inflammatory diseases from primary CNS lymphoma.

BACKGROUND: Interleukin 6 (IL-6) is a pleomorphic cytokine that can be found in the cerebrospinal fluid (CSF) in a wide spectrum of inflammatory pathologies of the central nervous system (CNS). OBJECTIVE: Our aim was to characterize the diagnostic significance of CSF IL-6 among various CNS inflammatory diseases with pseudotumoral lesions (CNSID) and primary CNS lymphoma (PCNSL). METHODS: We retrospectively analyzed the CSF IL-6 concentrations in 43 consecutive patients with suspected PCNSL. A total of 28 patients were positively diagnosed with PCNSL and 15 with CNSID. We verified the results with CSF IL-10, an established biomarker for PCNSL. RESULTS: In the PCNSL group, the median CSF IL-6 concentration was 8 pg/ml, interquartile range (IQR) 5-18.5. For the patients with CNSID, the median concentration was 70 pg/ml, IQR 5-1368. A group comparison showed significantly higher CSF IL-6 levels in patients with CNSID than in those with PCNSL (p = 0.032). Moreover, IL-6 was correlated with CSF cell count in the CNSID group (r = 0.56, p = 0.028), but not in the PCNSL group (r = 0.3, p = 0.13). We found significantly higher CSF IL-10 levels in patients with PCNSL than in patients with CNS inflammatory lesions (p < 0.001). DISCUSSION AND CONCLUSIONS: Our study suggests that CSF IL-6 levels could represent, in addition to CSF IL-10, a useful biomarker in the differential diagnosis of CNSID and suspected PCNSL.

Multifocal and multicentric low-grade oligoastrocytoma in a young patient.

Multiple primary central nervous system tumors are rarely seen in clinical practice and reported in the literature. The pathogenesis of multicentricity of primary tumors of the central nervous system still remains a debate, this pathology being found in almost two percent of reported tumor cases. Multifocal tumors are often described within the same hemisphere and supposed to be disseminated along the white matter tracts. On the opposite, multicentric tumors are found in the other hemisphere in subtentorial structures and are considered synchronous. We illustrate here the case of a young man admitted for symptoms of intracranial hypertension, diagnosed with multifocal and multicentric low-grade oligoastrocytoma with particular evolution and imagistic appearance.