Study of Intraoperative Squash Cytology of Intracranial and Spinal Cord Lesions with Histopathological Correlation.

Background & Objective: Central nervous system (CNS) tumors display significant diversity in clinical behavior and morphology. Timely intraoperative diagnosis is critical for surgical decision-making. Squash cytology is a rapid, cost-effective tool for evaluating CNS lesions intraoperatively, especially where frozen section has limitations. This study aimed to assess the utility and diagnostic accuracy of squash cytology in the intraoperative diagnosis of intracranial and spinal cord space-occupying lesions, with correlation to histopathology. Methods: This prospective study included 57 patients undergoing surgery for CNS lesions at Government Medical College from January 2019 to June 2020. Intraoperative squash smears were prepared and stained with rapid hematoxylin and eosin. The cytological diagnosis was compared with paraffin-embedded histopathology. Statistical analysis was performed to evaluate sensitivity, specificity, diagnostic accuracy, and concordance in tumor grading. Results: Among the 57 cases, 91% were neoplastic and 9% were non-neoplastic. Meningioma (33.3%) and diffuse astrocytic/oligodendroglial tumors (28.1%) were the most common neoplasms. The diagnostic accuracy of squash cytology was 94.73%, with high sensitivity and specificity. Cytological grading matched histopathological grading in the majority of cases. Diagnostic errors were mainly observed in tumors with poor smearability, high cohesiveness, or crush artifacts. Conclusion: Intraoperative squash cytology is a valuable diagnostic adjunct in CNS surgeries. It offers high accuracy and rapid turnaround and is particularly useful in resource-limited settings. While histopathology remains the gold standard, squash cytology significantly aids intraoperative decision-making.