Evaluation of Intraoperative Cytological Smears for Diagnosis of Brain Tumors with Special Reference to Immunohistochemistry

Diagnostic Accuracy of Intraoperative Brain Smear: A Meta-Analysis of Studies from Resource-Limited Settings

BACKGROUND

Intraoperative brain smear is an easy, rapid, and cost-effective technique for immediate diagnosis of brain tumors. Earlier studies have gauged its application on limited number of samples, but its diagnostic accuracy especially in low-resource settings, where its practice would be extremely helpful, is still undetermined. To investigate the diagnostic accuracy of intraoperative brain smear in resource-limited settings for diagnosis of brain tumors.

METHODS

A systematic search was conducted on PubMed, Google Scholar, Scopus, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Embase for all articles utilizing intraoperative brain smears that were extracted. Studies from low- and middle-income countries (LMICs) with test performance characteristics were selected and subsequent values were summarized using a hierarchical summary receiver operating characteristic (ROC) curve via STATA and pooled using a random-effects model on MetaDiSc 2.0.

RESULTS

Twelve studies consisting of 1124 patients were identified. Six studies included both adult and pediatric population groups, while 4 investigated adults and 2 included pediatric patients. The pooled diagnostic odds ratio (OR) was calculated to be 212.52 (CI: [104.27-433.13]) of Bivariable pooled specificity and sensitivity were 92% (CI: [86%-96%]) and 96% (CI: [93%-98%]), respectively.

CONCLUSIONS

Our study shows that intraoperative brain smear is not only an accurate and sensitive diagnostic modality in resource-rich settings, but it is also equally useful in resource-limited settings, making it an ideal method for rapid diagnosis.

Unveiling the potential application of intraoperative brain smear for brain tumor diagnosis in low-middle-income countries: A comprehensive systematic review

Background

Immediate intraoperative histopathological examination of tumor tissue is indispensable for a neurosurgeon to track surgical resection. A brain smear is a simple, rapid, and cost-effective technique, particularly important in the diagnosis of brain tumors. The study aims to determine the effectiveness of intraoperative brain smear in the diagnosis of brain tumors in low- and middle-income countries (LMICs), while also evaluating its sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy.

Methods

A comprehensive search of the literature was conducted using PubMed, Scopus, and Google Scholar. The retrieved articles were independently screened by two reviewers. The data was extracted, processed, and organized using Microsoft Excel.

Results

A total of 59 out of 553 articles screened were included in the final analysis. The sensitivity and specificity of the intraoperative smear of brain tumors were found to be over 90% in most studies. The PPV was consistently above 90% in 11 studies, reaching 100% in one study and the NPV varied, ranging from 63% to 100%, and the accuracy was found to be >80% in most studies. One recurrent theme in the majority of the included studies was that an intraoperative brain smear is a cost-effective, quick, accessible, and accurate method of diagnosing brain tumors, requiring minimal training and infrastructure.

Conclusion

Intraoperative brain smear is a simple, rapid, cost-effective, and highly sensitive diagnostic modality for brain tumors. It can be a viable and accessible alternative to more traditional methods such as frozen sections and can be incorporated into neurosurgical practice in LMICs as a reliable and efficient diagnostic tool.

Intraoperative squash Cytology of diffuse glioma not otherwise specified, of the Cerebellum

OBJECTIVE

Diffuse glioma arises anywhere in the CNS, but most frequent in the cerebral hemispheres. The tumor tends to be seen in children and in younger adults aged 20-30. We report one such case in an older female patient presenting the intraoperative cytology of the tumor.

CASE REPORT

A 48-year-old female was diagnosed by MRI with a tumor of cerebellum. Cytologic material was obtained during the resection of the tumor and diagnosed cytologically as glioma.

CONCLUSION

This case is presented to focus the ability of the intraoperative cytology in diagnosis of the glioma, using immunocytology and confirmed by histo- immunohistology.

Cerebrospinal fluid and intraoperative squash cytology of childhood ependymoma

Ependymomas are glial neoplasms of central nervous system originated from the ependymal lining of the brain ventricles and spinal cord central canal, and rarely exfoliated into cerebrospinal fluid (CSF). In this case we report the cytomorphological and immunocytomorphological features of ependymoma in CSF and intraoperative squash preparations, confirmed by histology.

Utility of Squash Cytology in Spinal Lesions with Special Reference to Ki67 Immunostain

BACKGROUND

Squash cytology is of significant importance in intraoperative consultation of central nervous system (CNS) pathology. There are several studies on squash cytology of CNS lesions, and only a few of them deal with spinal lesions alone.

AIMS

(1) To evaluate intraoperative squash cytology of spinal lesions. (2) To correlate cytological diagnosis with histopathological diagnosis and assess the diagnostic accuracy. (3) To study Ki67 expression on squash smears and determine whether it can assist in grading spinal tumours on cytology.

MATERIALS AND METHODS

A prospective study was conducted on 68 patients with clinico-radiologically diagnosed lesions of the spine. Intraoperative squash smears were stained with haematoxylin-eosin (H&E) stain, Papanicolaou (Pap) stain, and May-Grünwald-Giemsa (MGG) stain. Subsequently, histological diagnosis was made. Ki67 immunostaining was performed on squash smears and histology sections.

RESULTS

The sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy of squash cytology in spinal lesions were 84.6, 100, 100, 23.1, and 80.88%, respectively. On immunocytochemistry, the mean Ki67 labelling indices for grade I, II, and III tumours were 0, 0.33 and 9%, respectively.

CONCLUSION

Squash smear cytology is a rapid intraoperative technique for diagnosing spinal lesions, with high specificity and high positive predictive value. It is more effective in diagnosing neoplasms than non-neoplastic lesions. Ki67 immunostaining can be done on cytology smears to effectively differentiate between WHO grade I and grade II spinal tumours.

Utility of intraoperative squash cytology in diagnosis of paediatric central nervous system lesions

BACKGROUND

Role of squash cytology in intraoperative diagnosis of central nervous system lesions has been well established. Intraoperative diagnosis is especially important in paediatric CNS lesions as decision regarding gross total resection or near total resection or subtotal resection is crucial and radiotherapy and chemotherapy are best avoided in this age group. The aim of this study was to evaluate the utility of squash cytology of CNS lesions in paediatric age group and to assess its diagnostic accuracy, sensitivity, specificity, positive predictive value and negative predictive value.

MATERIALS AND METHODS

A prospective study was conducted on 42 paediatric patients with clinico-radiologically diagnosed CNS lesions. Intraoperative squash smears were stained with haematoxylin and eosin (H&E) stain. Diagnosis made subsequently on paraffin sections was taken as gold standard.

RESULTS

The overall diagnostic accuracy of intraoperative squash cytology of CNS lesions in paediatric age group was 73.80%. The sensitivity, specificity, positive predictive value and negative predictive value of this modality were 92.31%, 87.50%, 96.00% and 77.78%, respectively.

CONCLUSIONS

The spectrum of CNS lesions in paediatric age group is different from that in adults. Though the sensitivity and specificity of squash cytology in paediatric tumours are less than that of adults, it is an important tool for intraoperative diagnosis that guides regarding the extent of resection.