Intraoperative cytology (squash smear) in neurosurgical practice ? pitfalls in diagnosis experience based on 3057 samples from a single institution

Biopsy of Brain Lesions

Brain biopsy is essential for accurate diagnosis but is frequently avoided in veterinary medicine because of doubts about its safety, reliability, and clinical value. Data available from human and veterinary investigations suggest that such doubts are largely unwarranted. Many devices are available to guide minimally invasive biopsy but some can be costly to purchase and use, which can be problematic in veterinary medicine. Nowadays, costs can be substantially reduced by using 3-dimensional-printed guides.

Diagnostic utility of intraoperative squash smear cytology of Intra-cranial lesions in a resource limited setup of central India

Introduction

Intraoperative squash smear cytology is a useful diagnostic tool in case of CNS lesions. In resource poor countries where frozen section is unavailable, cytology is the mainstay method in giving a rapid intraoperative diagnosis which helps Surgeons regarding the extent of excision. The current study aims to assess the feasibility and accuracy of intraoperative squash cytology in evaluation of CNS tumors. Definitive diagnosis is confirmed by histopathological examination.

Materials and methods

This retrospective observational study was carried out at Department of Neuropathology. All patients diagnosed with space occupying lesion (SOL) in CNS were enrolled in the study. Intra-operative cytological diagnosis was compared to histopathological diagnosis. WHO classification of CNS tumors 2021 was used to classify tumors.

Results

Total seventy patients with intracranial SOLs were enrolled in this study who were operated for the same and their specimens were examined. Two samples were found to be inadequate and not included in final analysis. Mean age was 38.8 ± 17.85 (SD). Male-female ratio was 1.5:1 with 41 (60.3%) males and 27 (39.7%) females. 58 had neoplastic and rest 10 had non-neoplastic lesions. Complete concordance was achieved in 61 cases (Diagnostic Accuracy-88.2%). 3 (4.4%) cases showed partial concordance and 4 (5.9%) were discordant. For detection of malignant lesions through squash smear cytology overall Sensitivity was 73.9%, Specificity-97.8%, Positive Predictive Value-94.4% and Negative Predictive Value-88%.

Conclusions

Squash smear cytology is a simple, rapid and cost-effective method relying solely on the expertise of pathologist. High diagnostic accuracy can be achieved with squash cytology by taking clinical and radiological findings into consideration.

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.

Analysis of Intraoperative Squash Cytology of Central Nervous System Lesions and its Correlation with Immunohistopathology and Radiology

Context

Central nervous system lesions are diverse and remain one of the most challenging domains for neuropathologists. Intraoperative cytological diagnosis is now a universally accepted technique in diagnosis of central nervous system (CNS) lesions.

Aims

1) To analyze and compare cytomorphological features of CNS lesions in intraoperative squash smears with histopathology, immunohistochemistry, and preoperative radiological diagnosis and 2) to determine the diagnostic accuracy, sensitivity, and specificity of intraoperative squash cytology.

Settings and Design

Prospective study conducted at a tertiary healthcare centre over a period of two years.

Methods and Material

All biopsy materials which underwent squash cytology and histopathological examination were collected, evaluated, classified, and graded according to WHO classification of CNS Tumors, 2016. The squash cytosmear diagnosis was compared with histopathological features and radiological diagnosis. Discordances were evaluated.

Statistical Analysis Used

The cases were categorized into true positives, false positives, true negatives, and false negatives. Diagnostic accuracy, sensitivity, and specificity were calculated from 2*2 table.

Results

A total of 190 cases were included in the study. A total of 182 cases (95.70%) were neoplastic of which 87.36% were primary CNS neoplasms. Diagnostic accuracy in non-neoplastic lesions was 88.8%. Most common neoplastic lesions were glial tumors (35.7%), meningioma (17.3%), tumors of cranial and spinal nerves (12%), and metastatic lesions (12%). Diagnostic accuracy of squash cytology was higher in glial tumors (93.8%), meningioma (96.7%), and metastatic lesions (95.45%). Diagnostic accuracy of radiological modalities was 85.78%.

Conclusions

A good familiarity with cytomorphological features of CNS lesions, clinical details, radiological findings, and intraoperative impression of neurosurgeon enables the pathologist to improve diagnostic accuracy and reduce errors.

An Audit of Diagnostic Disparity between Intraoperative Frozen Section Diagnosis and Final Histopathological Diagnosis of Central Nervous System Lesions at a Tertiary Care Center

Introduction Evaluation of intraoperative squash smear and frozen section (FS) in central nervous system (CNS) neoplasms is consistently practiced for rapid assessment and has several advantages to its credence. It is an invaluable tool to ensure adequacy of tissue obtained to establish the diagnosis. Moreover, it aids in guiding the surgeon for critical decisions regarding the extent of resection. Although molecular markers have been integrated with morphology in the revised 2016 World Health Organization classification of brain tumors, precise morphological assessment still remains the foundation for the diagnosis and rapid intraoperative assessment of morphological details is equally critical and rewarding.

Objective This study aims to audit the diagnostic disparity between intraoperative diagnoses based on a combination of squash cytology and FS in cases of CNS lesions with gold standard, final diagnosis based on examination of formalin fixed paraffin embedded hematoxylin, and eosin-stained tissue sections.

Materials and Methods All intraoperative squash cytology and FS reported for CNS lesions from January 2017 to December 2020 were reviewed. The cases were categorized into three groups—group 1: when diagnosis of intraoperative diagnosis based on a combination of squash cytology and FS was same as the final histopathological diagnosis (concordant), group 2: partially concordant, and group 3: discordant cases.

Statistical Analysis Descriptive statistics was used to classify the data and diagnostic accuracy was calculated.

Results Complete concordance was present in 69.96% (191/273) cases, 20.1% (55/273) cases showed partial concordance, and 9.89% (27/273) cases were discordant with histopathological diagnosis. Out of the 27 discordant cases, misclassification of tumor type was the most common category (11 cases, 40%), followed by grading mismatch (7 cases, 25.9%), and misdiagnosis of tumor versus nontumor conditions (9 cases, 33.3%).

Conclusion Our study shows that combination of intraoperative squash cytology and FS shows a high percentage of accuracy in arriving at intraoperative diagnosis in cases of intracranial lesions. Regular audits of discordant cases should be conducted by surgeons and pathologists as part of a quality assurance measure to sensitize themselves with the potential pitfalls, minimizing misinterpretation and helping in providing a more conclusive opinion to the operating surgeons.

Scoring system for intraoperative diagnosis of intracranial schwannoma by squash cytology

OBJECTIVE

To assess the utility of a newly developed squash cytology (SC)-based scoring system for accurate intraoperative diagnosis of schwannoma.

METHODS

We first compared SC-based and frozen section (FS) diagnoses with final pathological diagnoses of schwannoma (16 cases), meningioma (39 cases) and low-grade astrocytoma (16 cases). Then, by logistic regression modeling, we identified features of SC preparations that were independently predictive of schwannoma. To develop a diagnostic scoring system, we assigned one point to each feature, and performed receiver operating characteristic analysis to determine the score cut-off value that was most discriminatory for differentiating schwannoma from the other tumour types. We then compared accuracy, sensitivity, and specificity of diagnosis before and after the application of the scoring system.

RESULTS

Overall diagnostic concordance rates for SC and FS were almost the same, at 73.2% (52/71) and 77.5% (55/71 cases), respectively. Of the 16 SC features entered into the analysis, the following nine were found to independently predict schwannoma, and were thus incorporated into the scoring system: smooth cluster margins, few or no isolated tumour cells, fibrillary stroma, spindle-shaped nuclei, parallel arrangement of stroma, parallel arrangement of nuclei, presence of anisonucleosis, absence of nucleoli, and hemosiderin deposition. A cut-off score of four items yielded the best sensitivity, specificity and predictive values for prediction of schwannoma. Use of the scoring system improved accuracy of intraoperative diagnosis from 80.3% to 94.4%, sensitivity from 56.2% to 93.8%, and specificity from 87.3% to 94.5%.

CONCLUSION

Our proposed SC-based scoring system will increase accuracy of intraoperative diagnosis of schwannoma vs non-schwannoma tumours.

Intraoperative Diagnosis of Central Nervous System Tumors: Challenges, Errors, Lessons Learned, and the Surgeon's Perspective

Background: Intraoperative crush smear is an adjuvant in diagnosing central nervous system (CNS) lesions on tissue sent for frozen section. Besides rapid decision-making, it also ensures that minimum injury is caused to the normal brain structures surrounding the intracranial neoplasm. A rapid intraoperative diagnosis helps the surgeon in planning the appropriate surgery.

Objective: Our objective is to review all the discordant cases between intraoperative and histopathological diagnosis and also to study the crush smear slides for morphological clues that could have been helpful in minimizing such errors, especially for an inexperienced neuropathologist/general pathologist. The surgeon’s perspective on the impact of these errors on management is also discussed.

Method: A prospective study of six years from 2013 to 2019 was conducted. Crush smears were made and stained with rapid hematoxylin and eosin (H&E). The rest of the tissue was processed for permanent tissue sections. Slides in which there was discordance between the intraoperative and permanent paraffin sections were reviewed to ascertain the reasons thereof.

Results: A total of 81 specimens of CNS tumors were sent for intraoperative consultation. Out of these, discordance was seen in 13 (16%) cases.

Conclusion: To minimize diagnostic errors, it is important to do regular analyses of the misinterpreted cases. Knowledge of the pre-operative radiological differential diagnosis is mandatory. Discussion with the surgeon regarding the clinical impact of the errors made will give a clearer picture to the pathologists regarding clinically relevant reporting during intraoperative consultation.

The Utility of Intraoperative Cytological Smear and Frozen Section in the Surgical Management of Patients with Cushing's Disease due to Pituitary Microadenomas

Cushing's disease (CD) is most commonly caused by a microadenoma, which at surgical exploration may not provide adequate tissue for pathologic diagnosis using standard techniques. We wished to determine the accuracy of intraoperative pathologic examination and whether the addition of intraoperative cytology increased the diagnostic yield. We reviewed the pathology reports from 403 operations on 341 patients with CD microadenomas from a single institution. The concordance rates of intraoperative diagnoses (cytology and frozen) with the final (paraffin section) pathological diagnosis were calculated. The overall pathologic confirmation of an adenoma (by either cytology, frozen, or paraffin section) was compared with the result from a historical cohort (using only standard frozen section analysis but not intraoperative cytology) and the pooled result from a meta-analysis of previously published data. The concordance rate between frozen section diagnosis and paraffin section histology was 390/403 (96.8%). The concordance rate between cytological smear and paraffin section histology was 213/246 (86.6%). In 54 cases (13.4%) with ultimate remission, pathologic confirmation was obtained only on intraoperative pathology (frozen section or cytology). Overall, pathologic confirmation was obtained in 326 operations (80.9%) by at least one pathological modality. The overall pathological confirmation of an adenoma was greater after the introduction of intraoperative cytology when compared with the historical control (67.1%, p = 0.015), and compared with the pooled rate of published data from the meta-analysis (72.1%, p < 0.001). Our findings suggest that addition of intraoperative cytological analyses during surgery for CD is an additional useful diagnostic tool for both neurosurgeons and pathologists.

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&amp;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.

Accuracy of Intraoperative Examination in Central Nervous System Lesions: A Study of 133 Cases

OBJECTIVE

Intraoperative examination is a highly valuable tool for the evaluation of central nervous system (CNS) lesions, helping the neurosurgeon to determine the best surgical management. This study aimed to evaluate the accuracy and to analyze the diagnostic disagreements and pitfalls of the intraoperative examinations through correlation with the final histopathological diagnosis in CNS lesions.

STUDY DESIGN

Retrospective analysis of intraoperative examination of CNS lesions and their final diagnosis obtained during 16 consecutive years. All diagnoses were reviewed and classified according to World Health Organization (WHO) grading for CNS tumors. Squash was performed in 119 cases, while frozen section and both methods were done in 7 cases each.

RESULTS

Among the 133 intraoperative examinations considered, 114 (85.7%) presented concordance and 19 (14.3%) diagnostic disagreement when compared with subsequent histopathological examinations. The sensitivity and specificity for the detection of neoplasia in intraoperative examination was 98 and 94%, respectively. The positive and negative predictive values were 99 and 88%, respectively. The accuracy for neoplastic and nonneoplastic disease was 85.7%. Disagreements were more frequent among low-grade (WHO grades I and II) neoplasms and nonmalignant cases.

CONCLUSIONS

Our results showed good accuracy of the intraoperative assessments for diagnosis of CNS lesions, particularly in high-grade (grades III and IV) lesions and metastatic neoplasms.

Utility of neurological smears for intrasurgical brain cancer diagnostics and tumour cell percentage by DESI-MS

Analysis of neurological smears by desorption electrospray ionization mass spectrometry (DESI-MS) is an emerging diagnostic strategy for intraoperative consultation in brain tumor resection. DESI-MS allows rapid sampling while providing accurate diagnostic information. We assess the chemical homogeneity of neurological smears using DESI-MS imaging and the quality of rapid DESI-MS diagnosis.

Vessel Morphologies of the Brain in Cytological Squash Preparations Are Useful for Intraoperative Diagnosis of High-Grade Astrocytomas

OBJECTIVE

The aim of this study was to determine whether intraoperative cytological evaluation of squash preparations is of benefit for differentiating high-grade from low-grade astrocytomas.

METHODS

Squash preparations of 42 astrocytomas were classified histologically according to the World Health Organization (WHO) 2007 classification system as grade II (n = 12), grade III (n = 11), and grade IV (n = 19) and were divided into 2 groups, namely a low-grade group (grade II) and a high-grade group (grades III and IV). The focus was on morphological cell and vessel characteristics, namely nuclear atypia, chromatin pattern, nuclear enlargement, variation in nuclear size, the presence of nucleoli, mitosis, tumor necrosis, cell density, multibranched vessels, and vascular dilatation, and these characteristics were compared between the low- and high-grade groups.

RESULTS

Nuclear atypia, the presence of coarse chromatin, variations in nuclear size, and cell density ≥200 per high-power field were significantly more prevalent in high- than in low-grade astrocytomas (p = 0.0407, p < 0.01, p < 0.01, and p < 0.01, respectively). Vessels with > 3 branches and a mean vessel diameter ≥20 μm were more prevalent in high- than in low-grade astrocytomas (p < 0.01).

CONCLUSION

Squash preparation cytology provides added benefit for the intraoperative identification of high-grade astrocytoma.

A Comparison between the Diagnostic Accuracy of Frozen Section and Permanent Section Analyses in Central Nervous System

Objective:

Using diagnostic pathological methods during surgery is a valuable means of determining the appropriate management for patients. Application of Frozen Section in CNS surgeries might face challenges due to friability of brain tissue and its relative inaccessibility. Various studies have evaluated the diagnostic acuity of frozen section compared to gold standard but results have been quite inconsistent. We conducted the present study to evaluate the accuracy of cryostat in diagnosing central nervous system tumors compared to the Gold Standard method.

Methods:

In this descriptive retrospective study, patients with definite diagnosis of central nervous system tumors made through histopathological evaluations were identified by reviewing the archives of pathology reports during 1996-2013. Demographic data, clinical history, radiologic findings and results of pathologic evaluations were extracted from the medical records and entered into SPSS statistical software v.22 for analysis.

Results:

A total of 405 patients diagnosed with CNS tumors were identified, of which 16 patients were not eligible and eventually 389 patients were included in the study. Regarding tumor category, subtype and grade, the results of the two methods were totally compatible in 303 patients (77.9%) and discrepant in 22.1% of cases. The tumors located in the middle fossa (p=0.031; OR=2.27; 95% CI: 1.08-4.79) and the posterior fossa (p=0.021; OR=2.46; 95% CI: 1.15-5.26) and the tumors biopsied using the stereotactic method (p=0.050; OR=2.42; 95% CI: 1.001-5.83) were associated with an increased chance of discrepant results between the two methods.

Conclusion:

Frozen section can correctly diagnose and affect the management of CNS lesions in 77.9% of cases. Finding ways to increase the sensitivity and specificity of this method and providing surgeons with more definite and exact intra-operative diagnosis can improve management of central nervous system lesions to a considerable degree.

Filter paper-assisted cell transfer (FaCT) technique: A novel cell-sampling technique for intraoperative diagnosis of central nervous system tumors

BACKGROUND

Intraoperative diagnosis of central nervous system (CNS) tumors provides critical guidance to surgeons in the determination of surgical resection margins and treatment. The techniques and preparations used for the intraoperative diagnosis of CNS tumors include frozen sectioning and cytologic methods (squash smear and touch imprint). Cytologic specimens, which do not have freezing artifacts, are important as an adjuvant tool to frozen sections. However, if the amount of submitted tissue samples is limited, then it is difficult to prepare both frozen sections and squash smears or touch imprint specimens from a single sample at the same time. Therefore, the objective of this study was to derive cells directly from filter paper on which tumor samples are placed.

METHODS

The authors established the filter paper-assisted cell transfer (FaCT) smear technique, in which tumor cells are transferred onto a glass slide directly from the filter paper sample spot after the biopsy is removed.

RESULTS

Cell yields and diagnostic accuracy of the FaCT smears were assessed in 40 CNS tumors. FaCT smears had ample cell numbers and well preserved cell morphology sufficient for cytologic diagnosis, even if the submitted tissues were minimal. The overall diagnostic concordance rates between frozen sections and FaCT smears were 90% and 87.5%, respectively (no significant differences). When combining FaCT smears with frozen sections, the diagnostic concordance rate rose to 92.5%.

CONCLUSIONS

The current results suggest that the FaCT smear technique is a simple and effective processing method that has significant value for intraoperative diagnosis of CNS tumors. Cancer Cytopathol 2017;125:277-282. © 2016 American Cancer Society.

Microvascular proliferation of brain metastases mimics glioblastomas in squash cytology

OBJECTIVE

Although microvascular proliferation is a key feature in the diagnosis of high-grade glioma, the characteristics of metastatic tumour vessels in smear preparations have not been documented. In this study, the vascular changes in metastatic brain tumours, using squash cytology to examine the vascular patterns in brain metastases, were reviewed.

METHODS

One hundred and forty-three squash smears of brain tissue, including 25 normal or reactive tissue, 23 malignant lymphomas, 8 grade I glioma (pilocytic astrocytoma), 23 grade II glioma (diffuse astrocytoma and oligodendroglioma), 42 grade IV glioma (glioblastoma), and 22 metastasis, were assessed. Two vascular patterns were assessed: thick and branching, and glomeruloid. The vessel density, nuclear layer and the number of vessel branches were compared. Furthermore, tumour vessels of brain metastases were analysed by histology and for immunohistochemical expression of CD34, α-smooth muscle actin (SMA) and high-molecular-weight caldesmon (h-CD).

RESULTS

Among 22 metastatic tumours, thick and branching vessels were found in 17 (77%) and glomeruloid vessels in 13 (59%). These incidences of microvascular proliferation patterns were similar to those of glioblastomas or pilocytic astrocytomas. Vessel density, nuclear layer and vessel wall branches were significantly higher in metastatic tumours than malignant lymphomas, grade II gliomas or normal brain tissues. Glomeruloid vessels consisted of CD34-positive cells and α-SMA-positive cells, and α-SMA-positive cells had a low h-CD expression. These immunohistochemical patterns were similar to those of high-grade gliomas.

CONCLUSIONS

The vascular features of metastatic brain tumours are similar to those of glioblastomas, suggesting that these microvascular proliferations contribute to the progression of metastatic tumours.

Utility and challenges in intraoperative consultation of spinal lesions by crush smear cytology

Background:

Various methods are used for intraoperative consultation of spinal lesions. Crush smear cytology is one such method that is accurate, rapid, and allows preservation of tissue for paraffin-embedded sections.

Aims:

To study the cytomorphology of various neoplastic and nonneoplastic lesions involving and compressing the spinal cord. To evaluate accuracy and discuss diagnostic pitfalls of crush smear cytology.

Materials and Methods:

Over a period of 5 years (January 2008 to October 2012), a total of 57 spinal lesions were referred for intraoperative cytology. In four cases, material was inadequate for evaluation, so we analyzed 53 cases.

Results:

Majority of lesions were neoplastic accounting for 86.79% whereas nonneoplastic lesions constituted 13.20%. Most of the tumors were low grade (82.92%). Overall accuracy rate was 90.56% with accuracy of 91.30% and 85.71% for neoplastic and inflammatory lesions, respectively.

Conclusion:

Crush smear technique is a simple, reliable, easy, and rapid method for diagnosing neoplastic and inflammatory lesions involving and compressing the spinal cord. It gives an immediate idea of prognosis so that surgeon can modify the operative procedure, if necessary.

Intraoperative diagnosis of central nervous system lesions: Comparison of squash smear, touch imprint, and frozen section

Background:

Intraoperative diagnosis of central nervous system (CNS) lesions is of utmost importance for neurosurgeons to modify the approach at the time of surgery and to decide on further plan of management. The intraoperative diagnosis is challenging for neuropathologists.

Aims:

The study was undertaken to determine the accuracy of cytological techniques (crush smears and touch imprints), frozen sections of space occupying lesions of the CNS and compare it with histopathological diagnosis.

Materials and Methods:

A total of 75 specimens received intraoperatively were subjected to cytology and frozen section study.

Results:

Neoplastic lesions formed the major group with 62 (82.7%) cases while 13 (17.3%) were nonneoplastic. The diagnostic accuracy of “squash smears” was found to be 89.2%. “Touch imprints” showed diagnostic accuracy of 78.4%. The low accuracy of touch imprints was attributed to poor cellular yield. The diagnostic accuracy of “frozen section” was 75.7%. However, the overall diagnostic accuracy was 96%.

Conclusion:

We believe that the cytololgical methods and frozen sections are complimentary to each other and both should be used to improve the intraoperative diagnostic accuracy in the CNS lesion.

Utility of squash smear cytology in intraoperative diagnosis of central nervous system tumors

Background:

Central nervous system (CNS) squash cytology (CSC) has established itself as a technically simple, rapid, inexpensive, fairly accurate, and dependable intraoperative diagnostic tool. It helps neurosurgeons immensely when management is dependent on it.

Aims:

This study aimed at finding out the utility of CSC as an intraoperative diagnostic tool from a neurosurgeon's perspective.

Materials and Methods:

Fifty prospectively registered patients with clinical diagnosis of CNS tumors were enrolled in the study. All the patients were subjected to magnetic resonance imaging (MRI). Intraoperative CSC was performed and smears were stained with Leishman and rapid Hematoxylin and Eosin (H and E) stain. The diagnosis of CSC was compared with MRI diagnosis and histopathological diagnosis. The CNS tumors were categorized based on clinical and therapeutic implications. Diagnostic accuracy, sensitivity, specificity, and positive and negative predictive value of MRI and CSC were calculated by using appropriate formulae.

Results and Conclusions:

The age range of the CNS tumors included in the study was 2 to 68 years. There was a slight female preponderance. Sensitivity, specificity, positive predictive value, and negative predictive value of preoperative MRI were 90.47%, 82.76%, 79.17%, and 92.31% respectively. These values of utility parameters for CSC were 100% for each of the clinical and therapeutic implications. It helped neurosurgeons in optimizing surgical procedure in 12 cases of meningioma. It influenced surgical management in 1 case of infratentorial pilocytic astrocytoma, and helped in the diagnosis and management of 9 unexpected tumors missed on MRI.

Squash cytology in neurosurgical practice: a useful method in resource-limited setting with lack of frozen section facility

BACKGROUND

Intra-operative cytology is an important diagnostic tool. It has shown to play an important role especially in the diagnosis of central nervous system tumours. The study was done to assess the feasibility of squash cytology as standalone diagnostic test in setting where frozen section facility is not available.

MATERIALS AND METHODS

Total 48 patients with various intracranial lesions were initially enrolled in the study. Patients were investigated by various radio-imaging techniques and routine blood investigations. Forty-one patients were operated at Netaji Subhash Chandra Bose medical college, Jabalpur. Intra-operative squash cytology diagnosis was performed and was correlated with histology diagnosis as gold standard.

RESULTS

Out of 41 patients, inflammatory lesions were diagnosed in nine patients while benign lesions [most common neurilemmoma and meningioma] were observed in 21 and malignant lesions [astrocytoma was most common] were diagnosed in 11 patients. Diagnostic accuracy of intra-operative squash cytology irrespective of lesion & site was 95%. We were able to inform about the diagnosis to neurosurgeon in 15 minutes in all cases and within 12 minutes in >85% cases

CONCLUSION

Squash smear cytology is reliable and rapid standalone diagnostic method and it can assist for intra-operative decision-making diagnosis of intracranial lesions in resource-limited settings where frozen section facility is not available.

Cytologic features of giant cell ependymoma: a case report and review of the literature

Here, we present a case of anaplastic giant cell ependymoma (GCE) occurring in a 15-year-old woman. Squash smear slides for intraoperative frozen section diagnosis revealed oval to round cell clusters with a papillary structure in a fibrillary background. This was occasionally accompanied by the presence of bizarre pleomorphic giant cells with hyperchromatic nuclei and prominent intranuclear inclusions. These intranuclear inclusions were a key clue to diagnosis of ependymoma. Histologic analysis revealed features of a high-grade tumor with perivascular pseudorosettes and bizarre pleomorphic giant cells, which established the diagnosis of GCE. We performed a review of literatures about the cytologic features of GCE, including our case, thus proposing that intraoperative frozen diagnosis of GCE would be established by squash smear preparations featuring the mitosis and necrosis, as well as the high cellularity, and the presence of giant cells showing hyperchromatic nuclei with eosinophilic cytoplasm and intranuclear inclusions/pseudoinclusions.

Crush intraoperatory analysis in craniopharyngioma

Intraoperative smear cytology provides a rapid and reliable intraoperative diagnosis and guidance to the neurosurgeon during surgical resection and lesion targeting. It also helps the surgeon to monitor and modify the approach at surgery. The aim of this article was a clinicopathological and cytomorphological intraoperative crush smear correlation in craniopharyngioma. Thirty craniopharyngiomas were included in this study. Twenty-seven cases were adaCP and only three cases were papCP. This series included 16 (53%) males and 14 (47%) females adult patients, aged from 15 to 86 years (median, 49 year). Two cases were frank errors, 12 cases showed partial correlation, 5 cases showed incomplete typing of the cell type, and 7 cases discrepancy in type of tumors. The percent error was 14%. Correlations with clinical details and radiological findings were helpful in improving the accuracy rate. Smear technique is a fairly accurate, relatively safe, rapid, simple, easily reproducible, and cost-effective tool to diagnose brain tumors. Smear cytology is of great value in intraoperative consultation of central nervous system pathology. The cytological aspects and smear patterns disclose important complementary diagnostic information for the histopathological examination.