HISTOLOGICAL AND IMMUNOHISTOCHEMICAL FEATURES OF BRAIN TUMORS: NEW APPROACHES TO THE DIFFERENTIAL DIAGNOSIS OF HIGH-GRADE GLIOMAS

Arsakhanova Gayna Abdullovna

Introduction. Gliomas of high malignancy (high-grade gliomas, HGG) remain one of the most aggressive and difficult to diagnose tumors of the central nervous system. Accurate histological verification of HGG is necessary to choose the optimal treatment strategy, but is complicated by pronounced intra- and inter-tumor diversity. The purpose of this study was to develop a comprehensive algorithm for differential diagnosis of HGG based on a combined analysis of histological and immunohistochemical parameters. Methods. The material for the study was biopsies of tumor tissue from 112 patients with verified HGG (anaplastic astrocytomas, glioblastomas, anaplastic oligodendrogliomas). An immunohistochemical study with antibodies to Ki-67, GFAP, EGFR, S100, and IDH1 was performed on paraffin sections. The density of cellular elements, the degree of nuclear atypia, the mitotic index, the nature of vascular proliferation and microvascular changes were evaluated. Statistical analysis was performed using binary logistic regression and ROC analysis methods. Results. An integrated histological analysis scheme HGG has been developed, which allows to objectify the differential diagnosis between anaplastic astrocytomas, glioblastomas and anaplastic oligodendrogliomas. Such signs as mitotic index >5 (sensitivity 87.9%, specificity 64.3%, p<0.01), microvascular proliferation (sensitivity 90.3%, specificity 85.7%, p<0.01), positive expression of GFAP (sensitivity 85.2%, specificity 73.1%, p<0.05) have the greatest diagnostic significance. The combined use of these criteria ensures diagnostic accuracy of up to 93.5%. Discussion. The combined analysis of key histological and immunohistochemical parameters makes it possible to neutralize the effect of intra-tumor diversity in the diagnosis of HGG [2]. The use of the developed algorithm reduces the risks of hypo- and overdiagnosis, provides a more accurate differentiation of HGG in comparison with traditional morphological approaches. The identification of the most informative signs of HGG makes it possible to formalize and accelerate the diagnostic process in practical neurooncomorphology.

Keywords:gliomas of high malignancy, histological diagnosis, immunohistochemistry, differential diagnosis, Ki-67, GFAP