Frozen section discrepancy in the evaluation of nonneoplastic central nervous system samples

A prospective multicenter assessor blinded pilot study using confocal laser endomicroscopy for intraoperative brain tumor diagnosis

In this multi-center, assessor-blinded pilot study, the diagnostic efficacy of cCeLL-Ex vivo, a second-generation confocal laser endomicroscopy (CLE), was compared against the gold standard frozen section analysis for intraoperative brain tumor diagnosis. The study was conducted across three tertiary medical institutions in the Republic of Korea. Biopsy samples from newly diagnosed brain tumor patients were categorized based on location and divided for permanent section analysis, frozen section analysis, and cCeLL-Ex vivo imaging. Of the 74 samples from 55 patients, the majority were from the tumor core (74.3%). cCeLL-Ex vivo exhibited a relatively higher diagnostic accuracy (89.2%) than frozen section analysis (86.5%), with both methods showing a sensitivity of 92.2%. cCeLL-Ex vivo also demonstrated higher specificity (70% vs. 50%), positive predictive value (PPV) (95.2% vs. 92.2%), and negative predictive value (NPV) (58.3% vs. 50%). Furthermore, the time from sample preparation to diagnosis was notably shorter with cCeLL-Ex vivo (13 min 17 s) compared to frozen section analysis (28 min 28 s) (p-value < 0.005). These findings underscore cCeLL-Ex vivo's potential as a supplementary tool for intraoperative brain tumor diagnosis, with future studies anticipated to further validate its clinical utility.

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.

Assessment of Quality of Frozen Section Services at a Large Academic Hospital Before and After Relocation

OBJECTIVES

To determine outcomes following relocation of frozen section services (FSS) and the implementation of a dedicated gastrointestinal frozen service.

METHODS

We reviewed our FSS 6 months prior to and following FSS relocation. Satisfaction surveys were sent to surgeons and pathologists. Survey feedback resulted in a pilot of gastrointestinal subspecialist frozen section coverage.

RESULTS

There were 1,607 and 1,472 specimens from 667 and 602 patients pre- and post-FSS relocation, respectively. There was a decline in median specimen delivery time to pathology (12 vs 10 minutes, P < .001) and an increase in median time from receipt in pathology to intraoperative diagnosis (20 vs 22 minutes, P = .008) in cases with intrapathology consultation but no change without consultation (median, 19 minutes). Intrapathology consultation decreased from 19.7% (317/1,607) to 11.5% (169/1,472) (P < .001). Discordance rates between frozen section and permanent section remained low and similar (2.0% [33/1,607] vs 2.7% [40/1,472], P = .24). There was no significant change in discordance with dedicated gastrointestinal subspecialty frozen section interpretation.

CONCLUSIONS

Relocation of FSS and dedicated subspecialty interpretation may improve surgeon satisfaction but can also create workflow challenges. Pathology departments need to achieve a balance between satisfaction and adequacy to establish best frozen section coverage models.

Real-time intraoperative surgical telepathology using confocal laser endomicroscopy

OBJECTIVE

Communication between neurosurgeons and pathologists is mandatory for intraoperative decision-making and optimization of resection, especially for invasive masses. Handheld confocal laser endomicroscopy (CLE) technology provides in vivo intraoperative visualization of tissue histoarchitecture at cellular resolution. The authors evaluated the feasibility of using an innovative surgical telepathology software platform (TSP) to establish real-time, on-the-fly remote communication between the neurosurgeon using CLE and the pathologist.

METHODS

CLE and a TSP were integrated into the surgical workflow for 11 patients with brain masses (6 patients with gliomas, 3 with other primary tumors, 1 with metastasis, and 1 with reactive brain tissue). Neurosurgeons used CLE to generate video-flow images of the operative field that were displayed on monitors in the operating room. The pathologist simultaneously viewed video-flow CLE imaging using a digital tablet and communicated with the surgeon while physically located outside the operating room (1 pathologist was in another state, 4 were at home, and 6 were elsewhere in the hospital). Interpretations of the still CLE images and video-flow CLE imaging were compared with the findings on the corresponding frozen and permanent H&E histology sections.

RESULTS

Overall, 24 optical biopsies were acquired with mean ± SD 2 ± 1 optical biopsies per case. The mean duration of CLE system use was 1 ± 0.3 minutes/case and 0.25 ± 0.23 seconds/optical biopsy. The first image with identifiable histopathological features was acquired within 6 ± 0.1 seconds. Frozen sections were processed within 23 ± 2.8 minutes, which was significantly longer than CLE usage (p < 0.001). Video-flow CLE was used to correctly interpret tissue histoarchitecture in 96% of optical biopsies, which was substantially higher than the accuracy of using still CLE images (63%) (p = 0.005).

CONCLUSIONS

When CLE is employed in tandem with a TSP, neurosurgeons and pathologists can view and interpret CLE images remotely and in real time without the need to biopsy tissue. A TSP allowed neurosurgeons to receive real-time feedback on the optically interrogated tissue microstructure, thereby improving cross-functional communication and intraoperative decision-making and resulting in significant workflow advantages over the use of frozen section analysis.

Intraoperative Frozen Cytology of Central Nervous System Neoplasms: An Ancillary Tool for Frozen Diagnosis

BACKGROUND

Pathologic diagnosis of central nervous system (CNS) neoplasms is made by comparing light microscopic, immunohistochemical, and molecular cytogenetic findings with clinicoradiologic observations. Intraoperative frozen cytology smears can improve the diagnostic accuracy for CNS neoplasms. Here, we evaluate the diagnostic value of cytology in frozen diagnoses of CNS neoplasms.

METHODS

Cases were selected from patients undergoing both frozen cytology and frozen sections. Diagnostic accuracy was evaluated.

RESULTS

Four hundred and fifty-four cases were included in this retrospective single-center review study covering a span of 10 years. Five discrepant cases (1.1%) were found after excluding 53 deferred cases (31 cases of tentative diagnosis, 22 cases of inadequate frozen sampling). A total of 346 cases of complete concordance and 50 cases of partial concordance were classified as not discordant cases in the present study. Diagnostic accuracy of intraoperative frozen diagnosis was 87.2%, and the accuracy was 98.8% after excluding deferred cases. Discrepancies between frozen and permanent diagnoses (n = 5, 1.1%) were found in cases of nonrepresentative sampling (n = 2) and misinterpretation (n = 3). High concordance was observed more frequently in meningeal tumors (97/98, 99%), metastatic brain tumors (51/52, 98.1%), pituitary adenomas (86/89, 96.6%), schwannomas (45/47, 95.8%), high-grade astrocytic tumors (47/58, 81%), low grade astrocytic tumors (10/13, 76.9%), non-neoplastic lesions (23/36, 63.9%), in decreasing frequency.

CONCLUSIONS

Using intraoperative cytology and frozen sections of CNS tumors is a highly accurate diagnostic ancillary method, providing subtyping of CNS neoplasms, especially in frequently encountered entities.

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.

The Role of Fast Cell Cycle Analysis in Pediatric Brain Tumors

Cell cycle analysis by flow cytometry has not been adequately studied in pediatric brain tumors. We investigated the value of a modified rapid (within 6 min) cell cycle analysis protocol for the characterization of malignancy of pediatric brain tumors and for the differentiation of neoplastic from nonneoplastic tissue for possible intraoperative application. We retrospectively studied brain tumor specimens from patients treated at our institute over a 5-year period. All tumor samples were histopathologically verified before flow-cytometric analysis. The histopathological examination of permanent tissue sections was the gold standard. There were 68 brain tumor cases. All tumors had significantly lower G0/G1 and significantly higher S phase and mitosis fractions than normal brain tissue. Furthermore low-grade tumors could be differentiated from high-grade tumors. DNA aneuploidy was detected in 35 tumors. A correlation between S phase fraction and Ki-67 index was found in medulloblastomas and anaplastic ependymomas. Rapid cell cycle analysis by flow cytometry is a promising method for the identification of neoplastic tissue intraoperatively. Low-grade tumors could be differentiated from high-grade tumors. Thus, cell cycle analysis can be a valuable adjunct to the histopathological evaluation of pediatric brain tumors, whereas its intraoperative application warrants further investigation.

Intraoperative pathology consultation: error, cause and impact

BACKGROUND

Correlation of intraoperative frozen section diagnosis with final diagnosis can be an important component of an institution's quality assurance process.

METHODS

We performed a quality assurance review of 1207 frozen section diagnoses from 812 surgical cases performed in the Hamilton Regional Laboratory Medicine Programme during a 6-month period in 2007. We reviewed the frozen section and permanent slides from all potentially discordant cases using a multiheaded microscope to arrive at a consensus pertaining to the type and reason for error. We reviewed the clinical record to determine whether there had been a potential adverse impact on immediate clinical management.

RESULTS

Frozen sections were most commonly requested for head and neck, nervous system and female genital tract specimens. Twenty-eight frozen sections (3%) were deferred. We identified 24 discordant diagnoses involving 3% of cases and 2% of specimens. The organ systems showing the greatest frequency of discordance relative to the total number from that system were the nervous system, head and neck, and the lungs. Of the errors identified, most occurred owing to diagnostic misinterpretation, followed by problems related to tissue sampling. There was a potential adverse impact on immediate clinical management in 14 cases.

CONCLUSION

Our results add to the Canadian data on the correlation between frozen sections and permanent sections; we note comparability to the concordance rates reported in the literature.

Utilization of frozen sections in the evaluation of chronic epilepsy-related cases

The role of frozen section consultation in the evaluation of chronic epilepsy-associated surgical excisions of brain tissue has not been previously examined. The study retrospectively reviews 335 cases in which a frozen section consultation was obtained in the setting of a resection for chronic epilepsy. In most cases (n = 323), 3 or fewer frozen sections were performed. The most commonly identified pathologies on final diagnosis included tumor or tumorlike lesions (79.1% of cases) and focal cortical dysplasia (20.9% of cases). Frozen section diagnoses discrepant with final diagnoses due to sampling error or misinterpretation were noted in 39 cases and most commonly involved a diagnosis of gliosis or tumor in the setting of a focal cortical dysplasia or diagnosis of gliosis in the setting of a low-grade tumor. In conclusion, frozen section consultation may be particularly useful in the evaluation of neoplasms arising in the setting of chronic epilepsy. Some epilepsy-associated pathology, such as focal cortical dysplasia, may be difficult to diagnose at the time of frozen section and such cases may not be an ideal target for intraoperative frozen section consultation.

Approach to the intraoperative consultation for neurosurgical specimens

Intraoperative consultation remains an invaluable tool in the initial evaluation of surgically excised specimens. Good communication is required between the pathologist and surgeon to obtain the best care for their mutual patient. Intraoperative consultation (frozen section, FS) provides a preliminary diagnosis for the surgeon and aids in guiding his/her subsequent surgical approach. For the pathologist, it serves to assess tissue adequacy in the context of the clinical and imaging features of the patient. FS can guarantee that the surgeon is in the desired anatomic location, but most often serves to ensure that adequate amounts of abnormal, and likely diagnostic, tissue will be available to the pathologist to render a final diagnosis on permanent sections. The preliminary evaluation of tissue at the time of intraoperative FS also guides the pathologist in the ordering of ancillary studies, some of which need to be performed on fresh or frozen tissues and must be sent at the time of the intraoperative consultation. This brief review will specifically focus on the role of the pathologist who is called to perform a FS for a neurosurgical specimen. We will discuss (1) the goals of the neurosurgeon for the intraoperative consultation, (2) how to achieve optimal communication between neurosurgeon and pathologist at the time of the FS, (3) what constitutes reasonable and unreasonable expectations by the neurosurgeon for the FS, (4) choices of techniques that can be used by the pathologist, (5) what tissue should be triaged, and (6) common discrepancies between FS and permanent section diagnoses in central nervous system disorders. The published literature on FS and permanent section discrepancies will be briefly reviewed so that pathologists will understand that some difficulties are inherent in neurosurgical specimens and are not specific to their practice, or to a given pathologist. Hopefully, this knowledge will enhance pathologists' confidence as they negotiate how best to handle this time-sensitive, and sometimes angst-producing, task.