Interobserver variability regarding ki67 proliferation index evaluation in ganglioglioma and anaplastic ganglioglioma

Abstract

Introduction. Ganglioglioma represents a rare neuroglial tumour, affecting most frequently the pediatric population and arising in the temporal lobe. Based on the Ki67 proliferation index, gangliogliomas can be divided into benign and anaplastic. The aim of our study was to assess the interobserver variability regarding the estimation of the Ki67 index, in order to establish if such a system could have a high reproducibility. Material and methods. The proliferative activity of 25 cases including benign and anaplastic ganglioglioma has been revised through the Ki67 marker (clone SP6). The cases have been evaluated by five different pathologists with different degrees of experience, in order to test the reproducibility. Additionally, all the cases were evaluated for immunoreactivity for CD34 (clone QBEnd/10). Results. Out of the 25 cases included in this study, 44% of them were diagnosed as anaplastic gangliogliomas.