Intraoperative Squash Cytology in CNS Lesions - How Fine is the Resolution?

Abstract

Introduction: With the advent of minimally invasive/ stereotactic neurosurgical techniques accurate localization of tumor and differentiation from surrounding normal brain parenchyma has become imperative to give maximal benefit of surgery and reducing collateral neurodeficit. Despite the advancement of non-invasive radiological tools, direct evidence from the microscope during the operation guides the surgeon and gives the patient optimal benefit of the surgery. The aim of this study is to correlate intraoperative squash cytology and final histopathological diagnosis and find out efficacy and reliability of squash as a diagnostic tool. Method/study design: A cross sectional observational study conducted in the Department of Neuropathology from August 2018 to June 2019. All neurosurgical cases received for both intra-operative diagnosis and histopathology sample were included. Results: Total ninety four cases of squash smear and corresponding histopathology with immunohistochemistry was studied and overall sensitivity of squash was calculated to be 91.3%. Individual sensitivity, specificity and positive predictive value for major lesions were also calculated. Conclusion: The role of intraoperative diagnosis in CNS tumors need not be overemphasized. It can achieve targeting of lesion and provide guidance to the neurosurgeon in modifying and monitoring the surgical approach.