Pitfalls in Diagnosis of Intraoperative Squash Cytology of Central Nervous System Lesions: Analysis of 545 Cases From a Single Center

Objective:Since the evaluation of the microsurgery techniques, intraoperative diagnosis of the central nervous system (CNS) lesions has gained importance. Squash smear (SS) preparation, imprint cytology, and frozen sections are the main diagnostic techniques. SS is challenging for the pathologist with various traps. The present study was undertaken to assess the diagnostic accuracy, pitfalls of the intraoperative SSs of the 545 CNS lesions, and compare it with the final paraffin diagnosis. Study Design:Intraoperative diagnosis of 545 CNS lesions were analyzed retrospectively from the files of the Pathology Department of Cukurova University, Medical Faculty, between the years of 2004 and 2012. The SSs were prepared at the time of intraoperative consultation and stained by hematoxylin and eosin. Results:Diagnostic accuracy was 94.4%. The overall sensitivity was 99.4% and the specificity was 91.5%. In addition, positive predictive value was 98.2%. Discussion:We have evaluated the discordant cases in our series and discussed the diagnostic pitfalls of SSs of CNS lesions. Awareness of the potential sources of misinterpreted cases together with the combination of radiology, clinical history, and location may increase the diagnostic accuracy.