Frozen section diagnosis: an audit

Preoperative, Intraoperative, and Postoperative Parathyroid Pathology: Clinical Pathologic Collaboration for Optimal Patient Management

Parathyroid disease typically presents with parathyroid hyperfunction as result of neoplasia or a consequence of non-neoplastic systemic disease. Given the parathyroid gland is a hormonally active organ with broad physiologic implications and serologically accessible markers for monitoring, the diagnosis of parathyroid disease is predominantly a clinical pathologic correlation. We provide the current pathological correlates of parathyroid disease and discuss preoperative, intraoperative, and postoperative pathology consultative practice for optimal patient care.

Sensitivity and specificity of frozen section diagnosis in orbital and adnexal malignancies

Purpose:

To analyze the diagnostic accuracy of frozen section in orbital and adnexal malignancies.

Methods:

A total of 55 cases between January 2006 and December 2011 for which intraoperative frozen section was performed for various orbital and adnexal lesions were included in the study. The frozen section diagnosis was compared with the permanent section diagnosis. Margin clearance was also compared between the two. Data were analysed using SPSS version 14. Odds ratio and cross-tabulation was used to perform the analysis.

Results:

The mean age at presentation was 51.46 ± 20 years. Eyelid was the most common site of involvement. Out of 55 cases, diagnosis was deferred in four cases (7.27%) on frozen section. Among 51 cases, 44 (86%) cases were concordant, whereas 7 (13%) cases were discordant. The sensitivity and specificity of frozen section compared to permanent section for diagnosis of malignancy was found to be 87.2% and 87.5%, respectively. The sensitivity and specificity of frozen section for diagnoses of basal cell carcinoma was found to be 100%, while it was 83.3% and 100% respectively for sebaceous gland carcinoma and 87.5% and 94.9% respectively for squamous cell carcinoma.

Conclusion:

Frozen section had high sensitivity and specificity when compared with permanent section for all three parameters studied. It is an important intraoperative tool that is increasingly being used in histopathological examination of ophthalmic lesions. However, it should not be used as a substitute for the permanent section and critical decisions based on it are best avoided.

Tissue expansion of lung bronchi due to tissue processing for histology - A comparative analysis of paraffin versus frozen sections in a pig model

AIM

Tissue shrinking due to fixation and processing is well known. However, the degree of shrinking varies significantly with the tissue type as well as the processing method and is not well studied in various tissues. In daily pathological routine workflow, histological specimens from frozen and paraffin sections are performed from the same tissue. In the present study we compared the thickness of bronchus walls obtained from paraffin and frozen sections.

METHODS

Pig lungs were frozen in ventilated condition in liquid nitrogen and 36 bronchi were isolated after dissection. Frozen sections of 5 μm thickness were performed and the remaining tissue was fixed and embedded in paraffin after fixation in 4% formalin. Frozen and paraffin sections from the same cutting edge were analysed after haematoxylin and eosin staining by measuring the wall thickness of the bronchi using high power fields of 400-fold magnification. In each bronchus 40 measurements were implemented at different wall positions distributed over the entire wall area. Summed up, in each group 1440 wall measurements were performed in total. Statistical analysis was conducted using the Wilcoxon test and t-test as well as Pearson's correlation coefficient with a significance level at P < 0.05.

RESULTS

The bronchial wall thickness was significantly (p < 0.001) smaller in frozen sections (median: 0.50 mm; min: 0.37 mm; max: 0.97 mm) compared to paraffin sections (median: 0.58 mm; min: 0.35 mm; max: 1.06 mm). The median difference between paraffin and frozen sections was 0.05 mm (min: -0.11 mm; max: 0.22 mm). The wall thickness ratio of both groups was as follows: frozen/paraffin section = 0.8609, thus yielding a difference between paraffin and frozen of 13.91%. High correlation was found between wall thickness measurements on paraffin and frozen sections (R = 0.87, p < 0.001).

CONCLUSIONS

The bronchus wall thickness in the frozen section was 14% reduced compared to the paraffin section. In routine pathology as well as in scientific studies these results are of relevance, as airway wall thickness represents a relevant marker for pathological interpretation, especially using CT image techniques.

Pitfalls in Frozen Section Interpretation: A Retrospective Study of Palpable Breast Tumors

Aims and background

The use of frozen sections for purposes of diagnosis is recognized to involve a degree of uncertainty. A retrospective study of breast specimen frozen section diagnoses was undertaken in order to analyse the major pitfalls.

Methods

Hard copy files from our archives relating to symptomatic (palpable) breast specimens obtained between 1983 and 1996 were reviewed.

Results

The review revealed 23 errors among the diagnoses on 2110 frozen specimens. Twenty-two of them were false-negative and 1 (a case of multiple intraductal papillomatosis with atypical ductal hyperplasia) was false-positive for malignancy. The factors contributing to the pitfalls were: 1) misinterpretation; 2) poor quality of the frozen sections (artifacts making the diagnosis difficult); 3) sampling errors during sectioning; 4) ignorance of the macroscopic features; 5) lesions difficult to interpret; 6) ductal carcinoma in situ as the only lesion in the specimen; and 7) sections not deep enough. Several of the factors sometimes occurred simultaneously.

Conclusions

Although the number of errors is relatively low, more stress should be placed on the preoperative diagnosis of breast lesions. Breast surgery frozen section should be used as rarely as possible for diagnostic purposes, despite the generally good diagnostic accuracy. However, it is reasonable to use frozen sections widely until the given preoperative diagnostic tools allow an appropriate preoperative workup, because it is the only way to keep histopathologists trained to interpret frozen sections.

Accuracy of Frozen Section with Histopathological Report in an Institute

INTRODUCTION

Frozen section helps in rapid intra-operative diagnosis. It is commonly used during surgical procedures to detect malignancy so that modifications of surgery can be decided at the time of surgery on the table. Frozen section is also performed for evaluation of surgical margins and detection of lymph node metastasis. In addition it is applied for detection of unknown pathological processes.The objective of this study was to assess the accuracy of frozen section diagnosis in comparison to gold standard histopathological diagnosis and to find concordance and discordance rate of frozen section with histopathological report.

METHODS

This was a cross sectional study of 41 frozen section samples done in the department of pathology of BP Koirala Institute of Health Sciences from September 2014 to August 2015. All frozen section samples with their permanent tissue samples sent for final histopathological evaluation were included in the study.

RESULTS

The overall accuracy of frozen section diagnosis was 97%. The sensitivity was 94%, specificity was 87%, positive predictive value was 90% and negative predictive value was 93%. The concordance rate was 90.2% and the discordance rate was 9.8%.

CONCLUSIONS

The results of frozen section varied in different organ systems and the common cause of discrepancy in our study were the gross sampling error and the interpretational error.

Frozen Section Evaluation of Margin Status in Primary Squamous Cell Carcinomas of the Head and Neck: A Correlation Study of Frozen Section and Final Diagnoses

Frozen section is routinely used for intraoperative margin evaluation in carcinomas of the head and neck. We studied a series of frozen sections performed for margin status of head and neck tumors to determine diagnostic accuracy. All frozen sections for margin control of squamous carcinomas of the head and neck were studied from a 66 month period. Frozen and permanent section diagnoses were classified as negative or malignant. Correlation of diagnoses was performed to determine accuracy. One thousand seven hundred and ninety-six pairs of frozen section and corresponding permanent section diagnoses were obtained. Discordances were found in 55 (3.1%) pairs. In 35 pairs (1.9%), frozen section was reported as benign, but permanent sections disclosed carcinoma. In 21 cases, the discrepancy was due to sampling and in the remaining cases it was an interpretive error. In 20 cases (1.1%), frozen section was malignant, but the permanent section was interpreted as negative. Frozen section is an accurate method for evaluation of operative margins for head and neck carcinomas with concordance between frozen and permanent results of 97%. Most errors are false negative results with the majority of these being due to sampling issues.

Discordance Between Intraoperative Consultation by Frozen Section and Final Diagnosis

Discrepancies between intraoperative consultations with frozen section diagnosis and the final pathology report have the potential to alter treatment decisions and affect patient care. Monitoring these correlations is a key component of laboratory quality assurance, however identifying specific areas for improvement can be difficult to attain. Our goal is to develop a standardized method utilizing root cause analysis and a modified Eindhoven classification schematic to identify the source of discrepancies and deferrals and subsequently to guide performance improvement initiatives. A retrospective review of intraoperative consultations performed at a tertiary level hospital and cancer center over a 6-month period identified deferrals and discrepancies between the intraoperative consult report and the final pathology report. We developed and applied a classification tool to identify the process errors and cognitive errors leading to discrepant results. A total of 48 (4.6%) discrepancies and 24 (2.3%) deferrals were identified from the 1042 frozen sections. Within the entire data set of frozen sections, the process errors (n = 26, 54.2%) were due to gross sampling (n = 16, 33.3%), histologic sampling (n = 8, 16.7%), and surgical sampling (n = 2, 4.2%). Interpretation errors (n = 22, 45.8%) included undercalls/false negatives (n=8, 16.7%), overcalls/false positives (n = 10, 20.8%), and misclassification errors (n = 4, 8.3%). Application of our classification tool demonstrated that the root cause of discrepancies and deferrals varied both between organ systems and by specific organs and that classification models may be utilized as a standardized method to identify focused areas for improvement.

Assessment of the Role of Intraoperative Frozen Section in Guiding Surgical Staging for Endometrial Cancer

Objective

The aim of this study was to assess the role of intraoperative frozen section (FS) in guiding decision making for surgical staging of endometrioid endometrial cancer (EC).

Methods

Medical records were collected retrospectively on 112 patients with endometrioid EC, who underwent total hysterectomy and bilateral salpingo-oophorectomy at the University of Arizona Medical Center from January 1, 2010, to December 31, 2014. Only patients with endometrioid adenocarcinoma, grade 1, less than 50% myometrial invasion, and tumor size less than 2 cm determined by intraoperative FS omitted lymphadenectomy; otherwise, surgical staging was performed with lymph node dissection. The FS results were compared with the permanent paraffin sections (PSs) to assess the diagnostic accuracy.

Results

The concordance rate of different variables between FS and PS in EC was 100%, 89.3% (100/112), 97.3% (109/112), and 95.5% (107/112), respectively, with respecting to histological subtype, grade, myometrial invasion, and tumor size. Diagnostic accurate rate of combined risk factors deciding surgical staging at the time of FS was 95.5% (107/112), and the discordance rate of all risk factors considered between FS and PS was 4.5%, resulting 3 cases (2.7%) undertreated and 2 cases (1.8%) overtreated.

Conclusions

Despite nonideal FS evaluation, intraoperative FS diagnosis for EC is highly reliable by providing guidance for the intraoperative decisions of surgical staging at our institution, and such guidelines may be referenced by the institutions with sufficient gynecologic pathology expertise.

Surgical Pathology and Intraoperative Consultation: An Audit

BACKGROUND

While intraoperative consultation has been used in Bangladesh for a long period of time, to date, there has been no published reporting on the performance of frozen sections. The current audit evaluates the performance of frozen sections in a well reputed medical center in Bangladesh, Anowara Medical Services.

OBJECTIVE

This retrospective study has been designed to measure the accuracy of frozen section diagnosis in a medical center in a third-world country, where many surgical procedures rely on intraoperative consultation.

METHODS

A series of 1379 intra- and peri-operative frozen section cases, from 2007 to 2014, was reviewed. Intraoperative tissue specimens received at Anowara Medical Services were processed for frozen sections. After examination of the frozen section that yielded the initial frozen section diagnoses, the frozen tissues were reprocessed for regular paraffin sectioning. These paraffin sections were examined by a second pathologist, and a final diagnosis was issued. The frozen section diagnosis and final diagnoses of all cases were retrospectively analysed to determine the accuracy of frozen section examination.

RESULTS

Overall, accurate diagnosis was made on frozen sections in 98.2% of the cases. The discrepant diagnoses were all clinically significant, i.e., there were discrepancies between benign and malignant diagnoses on frozen and paraffin sections. In 1% of the cases, diagnosis was deferred. Fifty percent of the deferred cases were benign. Two cases, received in formalin, were excluded. In both cases, the diagnosis was positive for malignancy. The number of false negative results (4 false negatives) was slightly lower than that of false positives (5 false positives). Specificity and sensitivity of 99.3% and 99.4% were achieved, respectively. In this study, the positive predictive value was 99.2% and the negative predictive value was 99.5%. Over the years, the number of discrepant diagnoses remained fairly constant.

CONCLUSION

The present method has a satisfactory rate of accuracy of frozen section diagnosis, which is comparable to other remote and recent published series. The results of this study offer a testament to the reliability of frozen section diagnosis rendered by qualified pathologists in Bangladesh and may serve as evidence in building confidence among the surgeons who use this service for improved patient care.

The Diagnostic Accuracy of Frozen Section Compared to Permanent Section: A Single Center Study in Iran

BACKGROUND

The diagnostic accuracy of frozen section as an important source of information in surgical pathology is important not only in the management of surgical patients but also as a measure of quality control in surgical pathology. In this study, we evaluated the diagnostic accuracy of frozen sections over a 6-year period in a teaching hospital in Iran.

METHODS

We retrospectively reviewed frozen sections performed in the Pathology Department of Taleghani Hospital (Shahid Beheshti University of Medical Sciences), Tehran, Iran from 2007 to 2013. The results were compared to the permanent sections to evaluate diagnostic accuracy, sensitivity and specificity, of frozen section test. Discordant cases were reassessed to find the reasons for discrepancy.

RESULTS

A total of 306 frozen section specimens from 176 surgical cases were evaluated. In eleven specimens (3.59%) the diagnoses were deferred. Of the remaining 295 specimens, 6 (2.03%) were discordant and 289 (97.96%) were concordant to permanent diagnoses. Specimens were primarily from the head & neck, thyroid, ovary, parathyroid and lymph nodes. The overall sensitivity, specificity, positive predictive value and negative predictive value of the frozen section compared to permanent section (as gold standard) were 92.95%, 99.55%, 98.50% and 97.80% respectively. Of the 6 discordant diagnoses, two (33.3%) were due to sampling error and four (66.6%) were due to interpretative errors.

CONCLUSION

Frozen section is an accurate and valuable test and can be relied on in surgical managements. The results of this study also confirm that the accuracy of frozen section diagnosis in our institution compares well with internationally published rates.

Application of intraoperative frozen section examination in the management of female breast cancer in China: a nationwide, multicenter 10-year epidemiological study

BACKGROUND

Intraoperative frozen section examination (IFSE) during breast cancer surgery can partly reflect the status of surgical treatment since the surgical method used directly determines the purpose of IFSE use in disease management. This study aims to investigate the application of, changing trends in, and factors influencing IFSE in the management of female breast cancer in China.

METHODS

We collected the sociodemographic and clinical data of 4,211 breast cancer patients between 1999 and 2008 and statistically analyzed these data using χ2 or Fisher's exact tests.

RESULTS

A total of 2,283 (54.22%) patients with breast cancer underwent IFSE. During the 10-year study period, IFSE use was associated with an increase in the number of sentinel lymph node biopsies (SLNB) and breast-conserving surgeries (BS) performed, with significant regional differences noted in this trend (P < 0.05). Patients' education, occupation, age, tumor size estimated by preoperative palpation, and the use of imaging examinations affected the purpose of IFSE use (P < 0.05).

CONCLUSIONS

Our results show that the purpose of IFSE in the surgical treatment of breast cancer in China is gradually approaching that in developed countries. We believe that policymakers must address the differences in breast cancer treatment based on the socioeconomic status of patients. Lastly, the use of IFSE for determining tumor characteristics should be avoided as far as possible, and patient education and breast cancer screening programs tailored to the Chinese population should be established. Our findings may guide the formulation of breast cancer control strategies in China and other low-income countries.

Frozen section diagnosis: is there discordance between what pathologists say and what surgeons hear?

OBJECTIVES

Communication in various medical settings is subject to misinterpretation. The frozen section (FS) diagnosis in patient care is dependent on successful communication between pathologists and surgeons. However, very few studies looking at FS errors analyzed postanalytic communication issues.

METHODS

A total of 300 consecutive cases, in which an FS was performed and corresponding surgical note was available, were studied. The FS diagnosis and surgeon's interpretation were recorded for all cases. Discrepancies were classified as major (clinical impact) or minor (no clinical impact).

RESULTS

We found 8 (2.7%) miscommunications, all with only minor clinical impact. These were attributed mainly to the surgeon's misinterpretation of a deferred diagnosis. Also contributing to miscommunication was the pathologist's use of nonspecific terminology such as "favor" or "scattered."

CONCLUSIONS

We found that the rate of miscommunicated FS diagnoses was low at our institution during the period of our study. However, the rate of miscommunication was similar to the much more widely recognized problem of sampling error.

Intraoperative consultation in digestive surgery. A consecutive series of 800 frozen sections

AIM

To assess indications and quality of frozen sections in digestive surgery.

PATIENTS AND METHODS

All the frozen sections from the department of digestive surgery from Amiens hospital performed between 01/07/2006 and 01/07/2010 were assessed. Assessment of frozen section forms, reading of pathology reports, and reviewing of frozen section slides were performed.

RESULTS

Eight hundred frozen sections were performed in 349 patients. From one to 14 surgical specimens were sent for frozen section (mean 2.3). Frozen sections were performed in 77% of the cases for cancer surgery (n=268), most of the time pancreatic surgery (28.4%) and liver surgery (24.6%). Frozen sections were performed in 69% of the cases for diagnosis, in 29% of the cases to assess surgical margins and in 2% of the cases to assess if tissue specimen was appropriate for pathological diagnosis. Frozen sections were sent all days of the week (except Saturday and Sunday), during all the year, between 8 H 30 and 17 H 15. Thirty-seven percent of the cases were sent between 12 H and 14 H. Response time was 15 minutes (3 to 57 minutes). Rate of differed diagnoses was 2%. Rate of discordant diagnoses was 3.4%.

CONCLUSION

Frozen section is a rapid and accurate tool in digestive surgery. Local adjustment of the organization of the Pathology Department could enhance the rapidity and the quality of pathology diagnoses.

Diagnostic accuracy of frozen section tests for surgical diseases

OBJECTIVE

To evaluate the accuracy of frozen section tests at different anatomical sites performed in an academic department of pathology.

METHODS

We conducted a retrospective study from a computerized database of all frozen section tests. These diagnoses were compared to definite paraffin, used as controls. The tests were divided into three groups: inconclusive, consistent and inconsistent, the latter being subdivided into false positives and false negatives. The main indications for examinations and anatomical sites involved with diagnostic disagreements were also analyzed.

RESULTS

Four hundred and thirty-three specimens were frozen tested, and the main indication was diagnostic (75.75%). In 404 tests (93.30%) diagnoses of biopsies in paraffin and frozen section were consistent. In 20 cases (4.62%) the results of frozen section biopsy were inconclusive and in 9 (2.08%) they were false negative. There were no false positive results. The most commonly assessed organ was the thyroid (25.64%). In the overall analysis, the body region most related with inconclusive diagnoses was the thyroid (seven cases) and in relation to specific sites it was the lungs/pleura/mediastinum (13.33%). Skin was the organ that showed more discordant diagnoses between frozen biopsies and paraffin.

CONCLUSION

The global accuracy of frozen section was 93.30%; for specific anatomical sites, diagnostic accuracy ranged from 86.67% to 100%.

Frozen section analysis of margins for head and neck tumor resections: reduction of sampling errors with a third histologic level

Frozen section analysis is an essential tool for assessing margins intra-operatively to assure complete resection. Many institutions evaluate surgical defect edge tissue provided by the surgeon after the main lesion has been removed. With the increasing use of transoral laser microsurgery, this method is becoming even more prevalent. We sought to evaluate error rates at our large academic institution and to see if sampling errors could be reduced by the simple method change of taking an additional third section on these specimens. All head and neck tumor resection cases from January 2005 through August 2008 with margins evaluated by frozen section were identified by database search. These cases were analyzed by cutting two levels during frozen section and a third permanent section later. All resection cases from August 2008 through July 2009 were identified as well. These were analyzed by cutting three levels during frozen section (the third a 'much deeper' level) and a fourth permanent section later. Error rates for both of these periods were determined. Errors were separated into sampling and interpretation types. There were 4976 total frozen section specimens from 848 patients. The overall error rate was 2.4% for all frozen sections where just two levels were evaluated and was 2.5% when three levels were evaluated (P=0.67). The sampling error rate was 1.6% for two-level sectioning and 1.2% for three-level sectioning (P=0.42). However, when considering only the frozen section cases where tumor was ultimately identified (either at the time of frozen section or on permanent sections) the sampling error rate for two-level sectioning was 15.3 versus 7.4% for three-level sectioning. This difference was statistically significant (P=0.006). Cutting a single additional 'deeper' level at the time of frozen section identifies more tumor-bearing specimens and may reduce the number of sampling errors.

Intraoperative Consultation/Final Diagnosis Correlation: Relationship to Tissue Type and Pathologic Process

Context.—The correlation of the diagnosis made at intraoperative consultation (IC) with the final diagnosis is one of the cornerstones of quality assurance in the anatomic pathology laboratory.

Objective.—To review correlation of IC diagnoses with final diagnoses during a 1-year period in a regionalized, multisite hospital setting in a major Canadian city.

Design.—One pathologist reviewed all surgical pathology cases at Calgary Laboratory Services from June 2004 through May 2005 that had an IC to extract the following data points: intraoperative diagnoses, final diagnoses, correlation between the two, anatomic site of the tissue on which the IC was requested, pathologic procedure requested of the IC, types of disagreements encountered, reasons for disagreement, and deferrals.

Results.—Intraoperative consultations occurred for 2812 specimens, of which 87 were discordant and 135 were deferred. Percent agreement was 96.75% (95% confidence interval, 96.08–97.42) with a κ statistic of 0.94 (95% confidence interval, 0.92–0.95). Lymph nodes for evaluation for metastases (427), thyroid/parathyroid (401), and central/peripheral nervous system (378) specimens were sent most frequently for IC, and the latter 2 tissue types accounted for the greatest number of disagreements. The most common assessments requested were the presence/ typing of a neoplasm (1161) and assessment of margins (730), which also accounted for the largest number of disagreements. Disagreements were most frequently due to interpretive (53) and gross sampling (23) errors; false-negative disagreements were nearly 3 times as common as false positives.

Conclusions.—The IC was an excellent diagnostic test. Agreement and deferral rates varied by specimen site and by type of assessment requested.

The Value of Monitoring Frozen Section–Permanent Section Correlation Data Over Time

Context.—The effectiveness of the long-term monitoring of errors detected by frozen section–permanent section correlation is unknown.

Objective.—To determine factors important in laboratory improvement in frozen section–permanent section discordant and deferral rates by participation in a multi-institutional continuous quality improvement program.

Design.—Participants in the College of American Pathologists Q-Tracks program self-reported the number of anatomic pathology frozen–permanent section discordant and deferred cases in their laboratories by prospectively performing secondary review of intraoperative consultations. Laboratories participated in the program for 1 to 5 years and reported their data every quarter. We calculated mean and median discordant and deferred case frequencies and used mixed linear modeling to determine if length of participation in the program was associated with improved performance.

Participants.—One hundred seventy-four laboratories self-reported data.

Main Outcome Measures.—Mean frozen–permanent section discordant and deferred diagnostic frequencies and changes in these frequencies over time were measured.

Results.—The mean and median frozen–permanent section discordant frequencies were 1.36% and 0.70%, respectively. The mean and median deferred diagnostic frequencies were 2.35% and 1.20%, respectively. Longer participation in the Q-Tracks program was significantly associated (P = .04) with lower discordant frequencies; 4- or 5-year participation showed a decrease in discordant frequency of 0.99%, whereas 1-year participation showed a decrease in discordant frequency of 0.84%. Longer participation in the Q-Tracks monitor was associated with lower microscopic sampling frequencies for discordant diagnoses (P = .04). Increased length of participation in the Q-Tracks program was significantly associated (P = .04) with lower deferred diagnostic frequencies.

Conclusions.—Long-term monitoring of frozen–permanent section correlation is associated with sustained improvement in performance.

Critical evaluation of frozen section margins in head and neck cancer resections

BACKGROUND

Negative resection margins are likely the most important prognostic factor for a patient with a head and neck squamous cell carcinoma. Frozen-section evaluation allows a positive margin to be corrected before surgical closure and reconstruction. A final pathology report is later issued after examination of all resected tissues. The accuracy of the final pathology report relies on accuracy in the preceding steps. The current process of margin reporting in head and neck cancer resections was studied to reveal possible waste and error in the system.

METHODS

Two hundred pathologists were surveyed about their center's current process of frozen-section margin evaluation. The authors of the current study used the membership log of the North American Society of Head and Neck Pathology and the list of the top 50 US cancer centers according to US News and World Report. The authors analyzed the process of frozen-section procedure using Toyota industry principles of quality improvement.

RESULTS

The majority of surgeons send small fragments of tissue from the surgical defect cavity. Many pathologists receive small unoriented tissue fragments. Many resample all or most of the margins for the final pathology report without anatomic orientation from the surgeon. Other pathologists do not sample any margins.

CONCLUSIONS

Final margin reporting redundancy and waste is due mainly to lack of anatomic correlation at interdisciplinary hand-offs. Oversampling and undersampling of margins may be occurring, and the accuracy of the final pathology report may be compromised. There is currently no consensus on how to best submit tissue for frozen-section evaluation of head and neck resection margins.

Frozen section: Its role in gynaecological oncology

The use of frozen section has greatly impacted on the care of the gynaecological oncology patient. Frozen section allows intraoperative evaluation to distinguish benign from malignant tumors in order to tailor the extent of surgery necessary. Frozen section diagnosis in gynaecological oncology is sufficiently sensitive and specific for clinical use. Generally, the false negative rate is low and the false positive rate is negligible. Deferred diagnoses or incompatible frozen section diagnosis is usually due to technical limitations especially for the mucinous ovarian tumors. This review summarises the available literature on the accuracy, limitations and role of frozen section for individual gynaecological tumors.

Interpretative problems and preparative technique influence reliability of intraoperative parathyroid touch imprints

CONTEXT

Identification of parathyroid tissue (PT) is crucial during parathyroid and thyroid surgery. Touch imprint preparation (TIP) examination is potentially a more time-effective and less labor-intensive approach than frozen section examination for identification of PT during intraoperative consultation. However, the reliability of PT-TIP remains controversial, and this fact has hindered its adoption as a replacement for frozen section examination.

OBJECTIVE

To assess the factors contributing to the relative lack of reliability of TIP in a retrospective study.

METHODS

Fifty randomly selected, alcohol-fixed, hematoxylin-eosin- and/or Diff-Quik-stained TIPs of specimens that had been submitted to confirm PT during intraoperative consultation were retrospectively reviewed by 5 observers. The observers were blinded to the final interpretation (based on hematoxylin-eosin-stained permanent sections), which included PT in 39 (78%) of the 50 specimens, thyroid in 9 (18%), lymph node in 1 (2%), and adipose tissue 1 (2%). Cases in which a unanimous diagnosis was not attained were re-reviewed by 3 observers.

RESULTS

Of 50 TIPs reviewed, a unanimous diagnosis was rendered in 33 cases (66%), including 27 (69%) of 39 PT cases, 5 (56%) of 9 thyroid cases, and the 1 lymph node case. Cytologic features observed in the TIPs that were unanimously accepted as being diagnostic of PT included the presence of small uniform cells in isolation or in small groups, round to oval nuclei, salt-and-pepper chromatin, occasional naked nuclei, and delicate vacuoles both within the cytoplasm and in the background. Re-review of the 17 remaining TIPs cases, in which diagnostic unanimity was not achieved, demonstrated that factors hindering assessment of the TIPs included hypocellularity (n = 5 cases), air-drying effect (n = 4), hemorrhagic background (n = 4), and presence of PT cells in follicular (thyroid-like) arrangements (n = 4).

CONCLUSIONS

The major factors influencing reliability of TIP of PT during intraoperative consultation are related primarily to interpretative problems and preparative technique. Awareness of interpretative problems and attention to preparation of TIPs may further enhance the accuracy of TIP during intraoperative consultation.

Accuracy of frozen section diagnoses of breast lesions after introduction of a national programme in mammographic screening

AIMS

By introducing mammography screening programmes, the size of the detected breast lesions became smaller and the histopathological interpretation problems greater. The study's aim was to analyse the risks and possible limitations of the frozen section method.

METHODS AND RESULTS

Frozen section consultations of breast lesions (n=559) 2 years before and 6 years after launching a national mammographic screening programme in 1992 were evaluated in regard of the benign/malignant ratio, tumour size, preoperative frozen section results and final permanent section diagnoses. The breast frozen section examinations of 1990 compared with those from 1998 declined from 70.7% (299/423) to 62.2% (260/418) (P < 0.01), the benign/malignant ratio from 1.09 to 0.54 (P < 0.0001), the rate of the conclusive, correct frozen section diagnoses from 96.3% to 91.9% (P < 0.03). The sensitivity dropped from 92.3% to 87.6%, the negative predictive value from 95.7% to 88.3%, whereas the negative likelihood ratio rose from 0.08 to 0.12. The 'small' (< or = 10 mm) invasive breast carcinomas increased from 14.2% to 22.3% (P < 0.01) and the 'in situ' carcinomas from 2.1% to 6.6% (P < 0.05).

CONCLUSIONS

The declining sizes of breast tumours (< or = 10 mm), especially from radiologically detected lesions and sometimes without a macroscopic correlate, create new limitations and changing indications in the histopathological interpretation. Considering the performance of new diagnostic methods (i.e. large core needle biopsies), frozen sections of surgical specimens should not be the primary diagnostic procedure for breast lesions and should be performed only after other preoperative methods have failed.

Accuracy of frozen section diagnosis in gynecology

OBJECTIVE

A retrospective study was undertaken to evaluate the accuracy of frozen section diagnosis in gynecological surgery.

METHODS

We compared the results of 792 consecutive gynecological frozen section diagnoses with their final diagnoses from January 1991 to June 1996. Slides for which the frozen section diagnosis was uncertain or incompatible with the final diagnosis were reviewed by an attending pathologist to determine the possible causes.

RESULTS

A total of 299 ovarian, 390 lymph node, 56 uterine lesions, and 77 other tissue samples were obtained. The frozen section diagnosis was compatible with the final diagnosis in 97.5% of cases. The sensitivity for nonbenign lesions was 90.9%, and the specificity was 99.5%. There were no false positives or overestimated cases; 1.3% of cases were falsely negative, 0.4% underestimated the degree of malignancy, and 0.9% were uncertain. Possible causes for incompatible or uncertain frozen section diagnoses were analyzed. The accuracy of frozen section diagnoses for ovarian, lymph node, uterine, and other tissues was also evaluated. Frozen section was found to identify correctly 13 of 17 ovarian malignancies metastaic from other organs, 14 of 15 germ cell malignancies, and 3 of 4 dysgerminomas. The low sensitivity in ovarian borderline malignancy was due to the even lower sensitivity in its mucinous subgroup. The relationship between section numbers and accuracy of frozen section diagnosis in mucinous ovarian tumors was assessed.

CONCLUSIONS

Frozen section diagnosis in gynecology is sufficiently accurate for clinical use, with a low false negative rate and an even lower false positive rate. Most incompatible frozen section diagnoses occurred in ovarian lesions, especially in mucinous ovarian tumors. Performing multiple sections (at least one section for every 10 cm in diameter) is recommended in the frozen section diagnosis of mucinous ovarian tumors.

Frozen-section services by telepathology: experience of 100 cases in the San-in District, Japan

The early experience is reported here of the use of intra-operative frozen-section service by telepathology using the integrated Service Digital Network (ISDN), a commercially available system that is being connected between the Department of Pathology of Tottori University and Matsue City Hospital, a distance of 30 km. The transfer rate is currently 64 kbit/s. The frozen-section service was conducted for a total of 117 tissue specimens (organs) from 100 patients between August 1993 and May 1995. The average time taken for examination of each specimen of frozen section was 13 min, ranging between 2 and 42 min. The average number of transmitted images was 6.2. Six cases necessitated more than 11 transmitted images to make a diagnosis, while 13 cases could be diagnosed from two images only. Correct and permissible diagnoses were obtained in 109 (93.2%) out of 117 specimens when comparing the telepathology diagnosis with that of direct microscopy. Improper or misdiagnosis was made for eight cases (specimens), which were misinterpreted as papillary carcinoma in Basedow's disease, adenoma and hyperplasia in two pheochromocytomas, solid-tubular carcinoma in phyllodes tumor, mastopathy in invasive carcinoma, metastatic carcinoma in astrocytoma, follicular lymphoma in reactive hyperplasia, and lymphadenitis in follicular lymphoma. In retrospect, diagnosis of these cases should have been deferred. From the results, it was concluded that the intraoperative frozen-section service by telepathology may be a worthwhile substitute for hospitals with limited accessibility to local pathology service, in spite of pitfalls in some cases. Well prepared, high-quality frozen section, sufficient verbal communication with surgeons, and a rather conservative attitude on the part of a well-trained pathologist seem to be the essential ingredients for reaching an accurate decision when using telepathology.

The accuracy of intraoperative diagnoses based on examination of frozen sections. A prospective comparison with paraffin-embedded sections

The accuracy of diagnoses based on examination of frozen sections was determined by comparing the results to those obtained by examination of tissues prepared using conventional methods (formalin fixation, paraffin-embedded tissue). One hundred ninety-four specimens were examined using the frozen section technique; 37 were examined to confirm a tentative diagnosis or to document lymph node metastasis and the remainder were examined to diagnose an unknown pathologic process. Of the 194 specimens examined, an accurate, specific diagnosis was obtained in 161 (83%); in 19 (10%), the pathologic process was correctly identified, but a specific diagnosis was not obtained; and in 2 (1%) the diagnosis was deferred. The remaining 12 (6%) were incorrectly diagnosed by the frozen section technique. When the number of specimens in which a specific diagnosis was obtained was combined with the number of specimens in which the pathologic process was correctly identified, the overall accuracy rate of the frozen section technique was 93%. There was no difference in the accuracy of the frozen section technique based on the reason for submission of the sample, source of tissue submitted, or the type of pathologic process (i.e., inflammatory or neoplastic). Of the 12 incorrect diagnoses, 4 (33%) were because of sampling errors and 8 (67%) were caused by interpretation errors.(ABSTRACT TRUNCATED AT 250 WORDS)

Intraoperative pathologic diagnosis of thyroid neoplasms. Report on experience with 504 specimens

Intraoperative pathologic examination with frozen section (FS) was performed on 504 specimens of thyroid tissue obtained from 457 patients over a period of 9 years. After examination of permanent sections (PS) a malignant neoplasm was diagnosed in 57 specimens (11.3%); 50 (87%) of these were primary thyroid carcinoma, four (8%) metastatic carcinoma, and three (5%) malignant lymphoma. The FS diagnosis was "benign" in 448 (88.9%), "malignant" in (30) 5.9%, and "deferred" in 26 (5.2%). The sensitivity of FS diagnosis of malignancy was 53% and the specificity and positive predictive value 100%. The negative predictive value was 97.8% and overall accuracy 97.9%. The PS disclosed a malignant neoplasm in 62% of specimens in which FS diagnosis was "deferred." Sixty-eight percent of papillary carcinomas, 87% of undifferentiated carcinomas, and a single case of medullary carcinoma were diagnosed with FS examination. A FS diagnosis of malignancy was not made in any of the ten specimens containing follicular carcinoma; in all ten the neoplasms were well-differentiated and eight were encapsulated and minimally invasive. The inability to diagnose follicular carcinoma intraoperatively with FS is the most significant factor accounting for the relatively low sensitivity of FS diagnosis of malignant thyroid neoplasms.

Interest in frozen section examination of margins and lymph nodes in laryngeal surgery

One hundred and one patients presenting with a squamous cell carcinoma of the larynx underwent surgery in our department between January 1980 and May 1985. In most of these patients, nodes were removed from the main lymphatic drainage pathways and subjected to immediate frozen section examination. The results from frozen section examination of the nodes were then compared with those from the surgical specimens of cervical neck dissections performed on the patients according to the classic rules. In addition, margin resections were made and examined by frozen section after removal of the tumour. In the event of a positive finding, these resections were continued until healthy tissue was reached, the specimens being examined in addition by classic methods. Immediate frozen sections enable the margins of the resection to be verified correctly. In our series we were brought to extend the limits of resection in 10 cases out of 68 (15 per cent). It can also be seen that the accuracy of the pathologist's reading of the frozen sections is satisfactory. The overall level of error is three out of 68 (4.5 per cent). All the errors correspond to false negatives. The aim of avoiding neck dissections in the presence of N0, thanks to nodal selection with frozen section, is not attained. We find a 6/61 rate of false negatives for N0-N1 (10 per cent) when we compare the frozen sections of the selected nodes and the neck dissections. This is due to the fact that the surgeon may be led astray by a reactive hyperplastic node whilst other less inflammatory neighbouring nodes are in fact the site of metastasis.

Accuracy of and reasons for frozen sections: a correlative, retrospective study

Previous studies on the accuracy of frozen sections (FS) were not based on the reasons for which the FS was performed. By omitting this important information, those studies reported FS accuracy of 94% to 97.4%. The current study analyzes the accuracy of FS diagnoses based on the reasons for which they were conducted. Of 482 specimens examined by FS in 1986, 41 were performed for evaluation of section margins of tumors, 29 for identification of unknown tissue, and 43 for detection of lymph node metastases. All 113 of these examinations proved to be 100% accurate. The remaining 369 FS were performed for diagnosis of an unknown pathologic process. Of these, 83.47% were precisely diagnosed; in 10.30%, the pathologic process was correctly, but not precisely, diagnosed; in 3.79%, the diagnosis was deferred; and the remaining 2.44% were incorrectly diagnosed (with no harmful consequences to the patients). By eliminating the cases of deferred diagnoses, the accuracy rate increased to 86.76%. Therefore, we suggest that the pathologist and the surgeon should not draw any conclusion from an inconclusive interpretation of FS and should proceed as though an FS had not been performed. When combining results of "precise diagnoses" with those of "correct pathologic process," the overall accuracy rate increased to 97%. The investigators conclude that FS should be used for a general diagnosis of a pathologic process rather than for an exact or precise diagnosis. Finally, we suggest that a similar survey of FS be periodically performed in every pathology department as part of its quality assurance program.

Accuracy of frozen section diagnosis of the salivary gland

Three hundred and one salivary gland lesions (162 benign, 72 malignant, and 67 benign non-neoplastic) of 677 cases were evaluated by use of intraoperative frozen sections by 66 pathologists. In seven patients, the diagnosis was deferred for permanent sections. In four cases (1.3%), the diagnosis at permanent section changed from one category of benign tumor to another, and in five cases (1.7%), from one category of malignant tumor to another. In four tumors, a frozen section diagnosis of benign was changed to malignant on permanent sectioning; all four involved acinic cell carcinomas. Only two tumors were incorrectly diagnosed as malignant. We conclude that diagnoses of most salivary gland lesions based on frozen section examination are reliable and accurate. However, the literature does indicate that caution should be exercised when malignant tumors are dealt with.