Analysis of 24 cases of epithelioid glioblastoma: Experience from a tertiary centre of North India

Ann Diagn Pathol. 2021 Feb:50:151679. doi: 10.1016/j.anndiagpath.2020.151679. Epub 2020 Dec 13.

Abstract

Background: Epithelioid glioblastoma (eGB) is a recently recognized and a rare variant of glioblastoma. This study aimed to describe the clinical, histological and immunohistochemical spectrum and outcome of eGB from a tertiary care hospital in north India.

Materials and methods: Twenty four cases of eGB diagnosed over past 10 years were reviewed with detailed morphological and immunohistochemical analysis (GFAP, EMA, Vimentin, Myogenin, INI-1, Cytokeratin, Synaptophysin, CD99, S100, MelanA, IDH1, ATRX, p16, EZH2, Ki-67, and BRAF V600E mutant antibody).

Result: The mean age was 29.9 years (3-54 years), with equal male and female patients. All had supratentorial tumor. All cases showed epithelioid cells in sheets; however, focal spindling (7 cases, 29.2%), grouping/nesting (6 cases, 25%) and papillary configuration (5 cases, 20.8%) were also noted. All showed microvascular proliferation (MVP) and all except one demonstrated areas of necrosis. INI1 was retained in all cases, while 2 showed patchy loss. EZH2 overexpression (>25%) was observed in 4 cases, while 5 cases showed loss of p16 expression. BRAF V600E mutant protein expression was seen in 12/23 (52.2%) cases. Outcome was available in 8 cases, out of which 6 (75%) experienced recurrence. The median survival was 25.5 months. Cases with tumor infiltrating lymphocytes had a better outcome.

Conclusion: eGB is a distinct variant of glioblastoma which has predilection towards younger age group. It shows high percentage of BRAF V600E mutation and a subset of it shows longer survival. Cases with presence of tumor infiltrating lymphocytes are associated with better outcome.

Keywords: BRAF V600E; Epithelioid glioblastoma; Radiotherapy; Tumor infiltrating lymphocytes; VE1.

MeSH terms

  • Adolescent
  • Adult
  • Brain Neoplasms / pathology*
  • Child
  • Enhancer of Zeste Homolog 2 Protein / metabolism
  • Epithelioid Cells / pathology*
  • Female
  • Glioblastoma / diagnosis*
  • Glioblastoma / metabolism*
  • Glioblastoma / mortality
  • Glioblastoma / radiotherapy
  • Humans
  • Immunohistochemistry / methods
  • India / epidemiology
  • Lymphocytes, Tumor-Infiltrating / pathology*
  • Male
  • Microvascular Density
  • Middle Aged
  • Mutation
  • Neoplasm Recurrence, Local / epidemiology
  • Neoplasm Recurrence, Local / pathology
  • Proto-Oncogene Proteins B-raf / metabolism*
  • Radiotherapy / methods
  • SMARCB1 Protein / metabolism
  • Survival Analysis
  • Tertiary Care Centers
  • Young Adult

Substances

  • SMARCB1 Protein
  • SMARCB1 protein, human
  • EZH2 protein, human
  • Enhancer of Zeste Homolog 2 Protein
  • BRAF protein, human
  • Proto-Oncogene Proteins B-raf