Cortical hemosiderin is associated with seizures in patients with newly diagnosed malignant brain tumors

Hemorrhage is common in brain tumors. Due to characteristic magnetic field changes induced by hemosiderin it can be detected using susceptibility weighted MRI (SWI). Its relevance to clinical syndromes is unclear. Here we investigated the patterns of intra-tumoral SWI positivity (SWIpos) as a surrogate for hemosiderin with regard to the prevalence of epilepsy. We report on 105 patients with newly diagnosed supra-tentorial gliomas and brain metastasis. The following parameters were recorded from pre-operative MRI: (1) SWIpos defined as dot-like or fine linear signal changes; (2) allocation of SWIpos to tumor compartments (contrast enhancement, central hypointensity, non-enhancing area outside contrast-enhancement); (3) allocation of SWIpos to include the cortex, or SWIpos in subcortical tumor parts only; (4) tumor size on T2 weighted and gadolinium-enhanced T1 images. 80 tumors (76 %) showed SWIpos (4/14 diffuse astrocytoma WHO II, 5/9 anaplastic astrocytoma WHO III, 41/46 glioblastoma WHO IV, 30/36 metastasis). The presence of SWIpos depended on tumor size but not on patient's age, medication with antiplatelet drugs or anticoagulation. Seizures occurred in 60 % of patients. Cortical SWIpos significantly correlated with seizures in brain metastasis (p = 0.044), and as a trend in glioblastoma (p = 0.062). Cortical SWIpos may confer a risk for seizures in patients with newly diagnosed brain metastasis and glioblastoma. Whether development of cortical SWIpos induced by treatment or by the natural course of tumors also leads to the new onset of seizures has to be addressed in longitudinal studies in larger patient cohorts.