Gemistocytes in newly diagnosed glioblastoma multiforme: Clinical significance and practical implications in the modern era

Background: Gemistocytes (GCs) in low grade gliomas are associated with rapid growth and worse prognosis. However, their clinical significance in glioblastomas (GBM) is a matter of debate. Aim of study: To investigate the clinical significance of the presence of GCs in newly-diagnosed GBM patients in the modern era. Methods: Computerized medical records from newly diagnosed GBM patients were retrospectively reviewed and extracted for demographic, clinical, radiological and pathological variables. Patients with at least 5% GCs of neoplastic cells were considered GC-GBM (group 1). All other cases were considered non-GC GBM (group 2). Group 1 was further divided into two subgroups: Low percentage GCs (group 1a, ≤ 20% GCs) and high percentage GC (group 1b, >20% GCs). Results: A total of 220 patients with newly diagnosed GBM were included. 14.5% were defined as GC-GBM (group I, n = 32) and 85.5% were defined as non-GC GBM (group 2, n = 188). 8.5% had ≤ 20% GCs (group 1a, n = 19) and 5.9% had > 20% GCs (group 1b, n = 13). Groups were similar for most epidemiological and clinical variables. There was a trend toward worse prognosis in group 1b. Several distinguished radiological and molecular features were observed in group 1. Conclusion: GCs are found in minority of naïve, newly diagnosed, GBM cases in adults. They seem to carry minimal implications on daily clinical practice. Higher percentage of GCs is associated with distinct radiological features such as multifocality that might be correlated with decreased OS. High-percentage GC-GBMs are also associated with increased prevalence of isocitrate dehydrogenase (IDH) mutations.