Tumor growth patterns in central nervous system tumors with astrocytic differentiation

Abstract

Background and Aim: Glial tumors with astrocytic differentiation are the most common primary malignant brain tumors. Hans Joachim Scherer established histological criteria based on hematoxylin and eosin (H&E) staining, which form the basis of the World Health Organization (WHO) glial tumor grades. The aim of this study was to investigate the incidence of Scherer structures across different classes of WHO grade tumors with astrocytic differentiation and determine whether secondary structures can be used as a grade-defining tool. Materials and Methods: Tumor samples were obtained from 36 patients with central nervous system (CNS) tumors with astrocytic differentiation between February 2018 and March 2019. The study was approved by the Committee on Ethics for Scientific Research, Medical University—Varna “Prof. Dr. Paraskev Stoyanov,” Protocol no. 20 [1] on April 26, 2012. The presence or absence of primary Scherer structures (pseudopalisading necrosis, glomeruloid vascular proliferation) and secondary Scherer structures (subpial palisading, fascicular aggregation, satellitosis around neurons, and blood vessels) was analyzed in H&E stained samples. Results: The samples were divided into two groups: 28 glioblastoma multiforme (GBM) cases and 8 lower grade astrocytoma cases. All 28 GBM cases exhibited pseudopalisading necrosis. Glomeruloid vascular proliferation was present only in 89.3% of the GBM cases. The GBM group also showed 67.9% subpial palisading, 78.5% fascicular aggregation of tumor cells, 96.4% perineuronal, and 100% perivascular satellitosis. The lower grade astrocytoma group had 0% pseudopalisading necrosis and glomeruloid vascular proliferation. Among all cases of lower grade gliomas, 50.0% showed subpial palisading, 87.5% fascicular aggregation, 100% perineuronal, and 100% perivascular satellitosis. Conclusions: Secondary Scherer structures can be considered as natural phenomena in glial tumors but cannot be used as features for grading.