Double Staining Immunohistochemistry and Digital Pathology: Moving Towards Standardization of the Proliferative Index Evaluation in Meningiomas

Background: Although several studies showed that high immunohistochemical Ki-67 index negatively influences the clinical course of meningiomas, especially in grade 1 and 2 neoplasm, the 5th edition of the World Health Organi-zation (WHO) Classification of Tumours of the Central Nervous System does not recognize it as a prognostic crite-rion. Issues related to Ki-67 assessment include interobserver variability, different cut-off values used by pathologists and the presence of a complex inflammatory tumour microenvironment, that may overestimate the proliferative index (PI). Methods In this paper, we described as Double Staining Immunohistochemistry (dIHC) EMA/Ki-67 highlights only neoplastic meningocytes better tha single slices evcaluation; then the application of Dig-ital Pathology (DP) can provide digital information for a more accurate count. Results and Future prospective dIHC and DP can support and standardize the evaluation of PI in meningiomas in daily routine.