Diagnostic utility of squash cytology in CNS lesions

Abstract

Background: Squash smears of CNS lesions are easy to perform, inexpensive and permit high diagnostic accuracy. Aims: 1) Study the cytology of various CNS lesions by squash technique.2) Assess the utility of squash preparation, as an aid to frozen section study.3) Assess the accuracy of squash preparation, by comparing it with histopathological section. Setting and Design: This study was conducted in the Department of Pathology over a period of 3 years. Materials and Methods: A total of 59 neurological specimens received in the department of pathology for frozen section were studied. Squash preparation was done on all the cases and stained with H and E staining. An intraoperative diagnosis was made on squash preparation and frozen section slides. The diagnosis on squash smears were compared with the final diagnosis. Results: Cytological correlation was seen in 54 out of 59 cases. Thus overall accuracy of squash cytology in intraoperative diagnosis of CNS lesions in our study was 91.52%. Erroneous intraoperative diagnosis was given in one case each of meningioma, anaplastic medulloblastoma, oligodendroglioma, arachnoid cyst and a case of gemistocytic astrocytoma. Conclusion: Intraoperative cytology is fairly accurate in the diagnosis of low grade astrocytoma, medulloblastoma, ependymoma, subependymoma, lymphoma, pituitary adenoma, metastases and certain inflammatory lesions. Diagnosis of high grade gliomas, certain cystic lesions and spindle cell lesions posed difficulties.