Diagnostic Accuracy of Squash Preparations in Central Nervous System Tumors

Background & Objectives: The accurate assessment of the diseased tissue is fundamental to the diagnosis and management of disorders of the central nervous system (CNS). The ?squash’ or ?crush’ technique has been universally employed in the intraoperative diagnosis of CNS tumors. The aim of our study was to evaluate the accuracy of squash preparation in diagnosing CNS tumors by comparing with histopathology. Methods: This was a descriptive study which included 63 patients with CNS tumors from whom most of the samples were collected by craniotomy. Squash smears were made and stained with H&E, Papanicolaou & May-Grunwald Giemsa stains. Paraffin sections were made from formalin fixed tissue sent separately. Results: Of 63 cases, squash cytology diagnosis correlated with histopathology in 56 cases with a diagnostic accuracy of 88.9%. A 100% accuracy was seen in pilocytic astrocytoma, anaplastic astrocytoma, glioblastoma, ependymoma, anaplastic ependymoma, choroid plexus papilloma, schwannoma, hemangioblastoma, craniopharyngioma, prolactinoma and metastases. Of the 7 cases which did not correlate with histopathology, one was a sampling error, 4 were diagnostic errors and 2 were instances of grading discrepancy. Conclusion: Squash preparations are a highly effective tool in the rapid intraoperative diagnosis of CNS tumors. It is a simple, reliable, cost effective procedure which in most cases can help the operating surgeon to come to a correct decision regarding the further management of the patients.