Intraoperative consultation for renal lesions. Implications and diagnostic pitfalls in 324 cases

Intraoperative consultation rarely is requested for lesions in the kidney. Of 324 renal lesions submitted for gross or frozen section intraoperative consultation, 199 specimens were submitted for gross consultation only; no diagnostic pitfalls were noted. The clinical implications and diagnostic pitfalls in 125 specimens submitted for frozen section were the focus of our study. Frozen section intraoperative consultation was requested to evaluate surgical margins in partial nephrectomy specimens, solid renal mass in an unusual clinical or radiologic setting, synchronous renal and extrarenal masses, cystic renal lesion, ureteral surgical margins for transitional cell carcinoma, multiple renal masses, solid mass in a diffusely cystic kidney, and renal injury. Among the 125 cases, the diagnoses were deferred in 17 (6 renal cell carcinomas with granular cytoplasm, 7 cystic lesions, 3 metastatic tumors, 1 leiomyoma). The frozen section diagnoses were incorrect owing to limited sampling in 5 and misinterpretation in 4 (melanoma vs angiomyolipoma, lymphoma vs angiomyolipoma, benign cyst vs cystic renal cell carcinoma, metastatic renal cell carcinoma vs pheochromocytoma). Awareness of distinctive indications for frozen section intraoperative consultation and diagnostic pitfalls should improve diagnostic accuracy and facilitate proper management of these lesions.     

Quality assessment of intraoperative frozen sections in a teaching hospital: an analysis of 847 consecutive cases

We evaluated the accuracy of 847 consecutive frozen section diagnoses in order to develop a quality control. We also evaluated the time needed to perform them. Frozen sections and final diagnoses agreed in 92.6% and disagreed in 1.7% (14 cases). 5.8% of the cases were deferred. The only case of false-positive frozen sections (0.1%) was due to a pathologist's misinterpretation. False-negative frozen sections were due to sampling errors: in 5 cases, diagnostic tissue was present only in permanent sections of the frozen block and in 8 cases diagnostic tissue was present only in the portion of the specimen not sampled by the frozen section. One hundred and ninety two frozen sections concerned thyroid neoplasms. Thirteen cancers were diagnosed on frozen sections, 2 cancers were considered as benign and 9 cancers had a differed diagnosis. The mean duration to perform the frozen sections was 21 minutes. In conclusion, intra operative frozen section diagnosis is rapid and reliable. Discrepancies are more often false negatives due to sampling errors. Although a high rate of differed diagnosis was observed in thyroid neoplasms, frozen sections remain useful for these lesions. Imprint cytology of thyroid nodules is advisable.     

Intra-operative frozen section technique for breast cancer: end of an era

Data on 2436 primary breast carcinomas diagnosed between 1992 and 2006 were collected to evaluate the rate of frozen section procedures performed over time. Frozen section procedures performed to evaluate resection margins for conservative surgery or sentinel node status were excluded. Over time, there was a decrease in the use of frozen sections indistinctly extended to all pT cancer categories. The rate of cancers diagnosed with frozen sections was 51.2% in 1999, and 0% in 2005-2006. In the same period, the adoption of cytology and core biopsy for breast cancer diagnosis increased from 40% in 1992 to more than 90% since 1999. In an audited diagnostic activity on breast pathology, the routine use of frozen sections on primary lesions was considered inappropriate, particularly in assessment of clinically non-palpable lesions, and should be limited to cases with inadequate pre-surgical sampling.     

An assessment of the value of frozen sections in gynecological surgery

In 203 consecutive gynecological operations where frozen sections were performed, 35.6% were from conditions of the ovary, 22.7% from the cervix, 18.2% from the endometrium, and 11.4% from the vulva. There were 0.5% false-positive, 1.0% false-negative and 2.0% deferred diagnosis. Incorrect interpretation was the cause of the single false-positive diagnosis, while the false-negative diagnoses were due to errors in block selection. The deferred diagnoses mainly occurred in gynecological conditions where diagnosis was difficult, required extensive sampling or a formal mitotic count. As in other surgical fields, gynecological frozen sections were used principally to guide the extent of surgery. The most valuable frozen sections were in those instances where the operation was affected most. These were on lymph nodes in cases of carcinoma of the vulva and cervix, myometrial lesions in young women where myomectomy was being considered, and ovarian tumours to distinguish primary from secondary tumours. Occasionally, frozen sections were also found useful to establish margins of vulval and cervical tumours, in hysterectomy specimens of endometrial carcinomas to determine prognostic factors, and in suspected recurrences and metastases of tumours to determine the adequacy of the biopsy material. Frozen sections in obviously benign conditions, e.g., ovarian cysts without papillary or solid areas, were found to be unnecessary. Frozen sections are contraindicated when only a small amount of crucial material is available, as the paraffin diagnosis may be compromised. Pathologists should have a clear idea of the role of frozen sections in gynecological surgery and work closely with the surgeon in the management of gynecological oncology patients.     

Accuracy of frozen section diagnosis in soft tissue tumors

This study was undertaken to analyze the accuracy of frozen section (FS) diagnosis of 118 soft tissue tumors with respect to the reasons for which the intraoperative consultation was indicated. Fifty-seven frozen sections were performed for the diagnosis of an unknown pathologic process. Complete agreement was established in 40.3% and the correct pathologic process in 43.9%, the diagnosis was deferred in 14%, and the remaining 1.8% were diagnosed incorrectly. Examination for determination of the adequacy of resection margin (22 cases), lymph node or skip metastases (23 cases), residual or recurrent tumor after previous surgery (29 cases), viable tumor tissue after previous locoregional or systemic therapy (ten cases), and identification of the specimen (five cases) proved to be 95.5%, 95.7%, 96.6%, 90%, and 100% accurate. Considering the whole series, an erroneous answer to a question posed by a surgeon was given in four cases (two false positive and two false negative), of which two cases were a sampling error made by pathologist. Intraoperative consultation by FS in soft tissue tumors is (a) reliable for general rather than exact diagnosis in defining the previously unknown pathologic process and (b) mandatory in evaluating resection margins and any discrepancies between preoperative cytologic and intraoperative gross impression.     

A retrospective analysis of the diagnostic accuracy and technical quality of frozen sections in detecting hepatobiliary lesions

IntroductionPathological consultation on intraoperative frozen sections plays a crucial role in the management of patients undergoing surgical therapy, and is also a key indicator for quality assurance in anatomical pathology. This study aimed to evaluate the diagnostic accuracy and technical quality of frozen sections in detecting hepatobiliary lesions with malignant potential.Patients and methodsA retrospective database review was performed for 1208 cases intraoperative pathology consultation who underwent hepatobiliary lesions resection at our institution from 2016 to 2020. The intraoperative consultation cases during a 5-year period were reviewed and analyzed, including the measurement of the diagnostic accuracy and turnaround time of frozen sections, the reasons for discrepancies, and the rates of discordance and deferral.ResultsIn this study, we confirmed that the overall accuracy, sensitivity and specificity were 95.3 %, 96.3 % and 96.6 %, respectively, in distinguishing benign from malignant lesions. The rates of deferred and discordant diagnoses were 2.57 % and 2.2 %, respectively. The overall frozen section turnaround time was 22.1 min. The most common cause of deferred and discordant was poor section quality, the lesion of bile duct margin on the frozen section, misinterpretation of difficult and complicated cases, etc.ConclusionsThis study confirms that the intraoperative frozen sections can serve as a rapid, accurate and robust method for the pathological diagnosis of suspected hepatobiliary lesions. However, it should be noted that some poor technical problems, pathological assessment of tumor margin and difficult cases are the most frequently causes of deferred and discordant interpretations.     

Accuracy of frozen section in the diagnosis of liver mass lesions

OBJECTIVE: To evaluate the diagnostic accuracy of intraoperative frozen sections diagnosis of liver lesions thought to be malignant tumours. METHODS: 285 frozen sections of liver from 173 patients were reviewed. The examinations were done between 1998 and 2004. RESULTS: Final histological diagnosis was divided into positive (32%) and negative (68%) for malignancy. In four cases (2%), diagnosis was deferred to paraffin section. There was one false positive and two false negative diagnoses. Sensitivity was 96.9% and specificity was 99.1%, and the overall accuracy to determine the lesions was 95%. The cases were further analysed to ascertain the nature of diagnostic difficulties, which comprised pathological misinterpretation, sampling error, and technical imperfections. Biliary hamartoma was the most common entity that was confused with malignant tumours in frozen sections. CONCLUSIONS: The data are in accordance with those of similar studies in other sites, and confirm that the frozen section is an accurate and reliable method for intraoperative diagnosis of suspected liver lesions.     

Interinstitutional comparison of frozen section consultation in small hospitals: a College of American Pathologists Q-Probes study of 18,532 frozen section consultation diagnoses in 233 small hospitals

OBJECTIVE: To study pathology intraoperative consultation practices and the accuracy of diagnoses made by frozen section. DESIGN: In 1994, participants in the College of American Pathologists Q-Probes laboratory quality improvement program each completed questionnaires and prospectively collected data on up to 20 frozen section procedures performed over a 5-month period. SETTING: Surgical pathology laboratories serving private and public hospitals with 300 or fewer occupied beds. PARTICIPANTS: Two hundred thirty-two North American institutions and one New Zealand institution. MAIN OUTCOME MEASURES: The discordance and deferral rates of frozen section diagnoses and the reasons for frozen section discordance relative to corresponding diagnoses made on permanent (paraffin) sections. Calculation of frozen section discordance rates excluded diagnoses of subtypes or grade of malignancy, biopsies on specimens in which there was no gross lesion (eg, mammographic specimens), thyroid follicular lesions, tissue taken only to determine adequacy for other studies (eg, estrogen-binding proteins), and frozen sections performed to evaluate margins of specimens oriented en face. RESULTS: Out of 18,532 frozen section diagnoses performed on 327,884 surgical cases, 859 (4.6%) diagnoses were deferred until permanent sections were available for review; 17,357 (98.2%) nondeferred diagnoses agreed with, and 316 (1.8%) disagreed with, those diagnoses rendered on permanent sections. The most common cause of discordance was underdiagnosis of neoplasia, usually due to block- or tissue-sampling errors. CONCLUSIONS: We recommend that laboratories routinely monitor frozen section discordance, cut additional sections deeper into the frozen block and/or sample additional tissue when the initial frozen section diagnosis is negative or nonproductive, reconcile all discordant frozen section diagnoses in the final report, and periodically assess the value of performing frozen section examinations.     

Correlation of fine needle aspiration cytology and frozen section biopsies in the diagnosis of thyroid nodules.

AIMS: To evaluate the correlation of fine needle aspiration (FNA) cytology and frozen section biopsy in the diagnosis of thyroid nodules. METHODS: The medical records of 662 patients who underwent FNA cytology of the thyroid and thyroid surgery were analysed. Frozen section biopsies were taken from 586 of the 662 patients. The diagnostic correlations of FNA cytology, frozen section, and both FNA cytology and frozen section with definitive histological assessment were evaluated. RESULTS: Among the 662 patients who received FNA cytology, there were 356 cases (53.8%) diagnosed as benign, 114 cases (17.2%) as malignant, 148 cases (22.4%) as indeterminate, and 44 cases (6.6%) as unsatisfactory. The positive predictive value for the detection of malignancy by FNA cytology was 92.1% and the negative predictive value was 95.2%. The incidence of malignancy in the indeterminate cytological diagnosis was 23%. The diagnosis from frozen sections was benign in 445 cases (75.9%), malignant in 134 cases (22.9%), and deferred in 7 cases (1.2%). By frozen section, the positive and negative predictive values were 97% and 95.5%, respectively. Diagnostic accuracy up to 98% was achieved when FNA cytology and frozen section diagnoses were in agreement. No false positives were observed when FNA cytology and frozen sections were both positive for malignancy. When FNA cytology and frozen section diagnoses were discordant, frozen section showed a higher accuracy (78.9%) than FNA cytology (21.1%). In the face of an indeterminate or unsatisfactory cytological diagnosis, the diagnostic accuracy of frozen sections reached 92.6%. CONCLUSIONS: The results confirm that FNA cytology is a useful tool in the initial evaluation of thyroid nodules. Intraoperative frozen section is a valuable procedure to confirm the cytological diagnosis and identify malignancy in patients with indeterminate or unsatisfactory cytological diagnosis. With reliance on frozen sections as an intraoperative guide of thyroid surgery, the possibility of unnecessary extensive surgery and the need for the second operation are considerably lower.     

Utility of intraoperative consultation touch preparations

Although intraoperative touch preparations (TPs) often are performed in conjunction with frozen sections, the comfort level of using TPs in actual practice and the effect of TP quality and cytologic experience on diagnostic accuracy have not been measured. To investigate the utility of intraoperative TPs and to compare them with that of frozen sections, five pathologists of differing levels of cytologic experience retrospectively reviewed 122 intraoperative TPs and frozen sections. Accuracy rates for individual pathologists were calculated and the accuracy using TPs was compared to that of frozen sections. TP accuracy was correlated with TP quality and cytologic experience. The mean rates of correct, incorrect, and atypical TP diagnoses were 88.5%, 4.1%, and 7.4%, respectively. The mean rates of correct, incorrect, and deferred frozen section diagnoses were 86.1%, 2.5%, and 11.9%, respectively. For the four pathologists with cytologic experience, both TP and frozen section diagnostic accuracy rates were similar; however, the pathologist who lacked cytologic experience had lower TP diagnostic accuracy. All pathologists who had cytologic experience requested a frozen section for cases with an atypical or incorrect TP diagnosis. In cases with a correct TP diagnosis a frozen section was requested 46.3% of the time. TPs of greater technical quality were associated with higher diagnostic accuracy. In conclusion, the use of performing TP and frozen section are complementary and result in increased diagnostic accuracy. For some pathologists, TPs may replace frozen sections in over 50% of cases.     

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.     

Frozen section diagnosis: an audit.

A consecutive series of 1000 operative frozen section diagnoses was reviewed. Correct diagnosis was made at the time in 96.5% of the cases. Clinically relevant errors were found in 1.3% of the cases and unimportant errors in 0.9%. Diagnosis was deferred, to await subsequent paraffin sections, in a further 1.3%. All the errors and provisional diagnoses in the deferred cases were conservative false negative results; no false positive diagnosis of malignancy was made. The cases of incorrect or deferred diagnosis were analysed to ascertain the origin of the difficulties, which comprised: technical imperfection (three cases); the focal nature of the lesion (14); and pathological misinterpretation (28). More than one of these factors played a part in eight cases. Further retrospective assessment indicated that the factors leading to error or deferred diagnosis were avoidable in 57% and potentially avoidable in 43% of cases. Misinterpretation was the single factor responsible for all avoidable misdiagnoses or deferred diagnosis. None the less, unavoidable factors led to erroneous or deferred diagnosis in about 2% of operative frozen section requests. Using present methods this seems to be the irreducible minimum of failures to make the correct diagnosis when frozen sections are assessed.     

15例硬化性肺细胞瘤冰冻切片与临床病理特征分析

目的：回顾性分析肺硬化性肺细胞瘤组织学及临床病理特点,提高快速冰冻诊断的准确性。方法：对15例经手术切除并诊断为硬化性肺细胞瘤的病例及2例冰冻误诊为硬化性肺细胞瘤的其他病变进行回顾性分析,包括冰冻及常规切片、免疫组织化学染色,结合临床病理特征进行总结。结果：本组15例硬化性肺细胞瘤,女性13例,平均年龄46岁;临床诊断肺癌6例,余9例为其他良性病变;冰冻切片诊断6例硬化性肺细胞瘤,1例炎性假瘤,1例错构瘤,2例肺癌,3例良性病变,2例延迟诊断;肿瘤常由乳头、硬化、实性、出血4种结构中的2种或多种混合而成。冰冻切片中10例见2种组织结构,4例见3种组织结构,1例见4种组织结构;圆形细胞TTF-1、EMA(+),表面上皮细胞TTF-1、EMA和CK(+),两种细胞Ki-67指数<2%。冰冻误诊为硬化性肺细胞瘤的2例,石蜡证实1例为混合亚型腺癌,1例为肺泡性腺瘤。结论：硬化性肺细胞瘤临床和影像学易误诊为癌,冰冻切片诊断准确率低。冰冻及石蜡切片中,常可见2种或2种以上组织结构;冰冻切片中以乳头状为主时,易误诊为腺癌;以实性为主时,易误诊为类癌。借助免疫组织化学指标,常可确诊。     

Potential pitfalls in the frozen section evaluation of parenchymal margins in nephron-sparing surgery

With advances in radiographic imaging, there has been an increase in the incidental detection of small renal cell carcinomas, with a resultant increase in partial nephrectomies for these tumors. Partial nephrectomy often necessitates assessment of renal parenchymal margins by frozen section. To determine the most common problematic "lesions" encountered on renal parenchymal margins, we evaluated all diagnostically challenging frozen sections that had been referred to a genitourinary pathologist. Frozen sections with detached atypical cells and crushed tubules were the most common lesions that presented diagnostic uncertainty. We found that normal constituents of renal parenchyma, namely tubules and glomeruli, can be mistaken for neoplasia. Neoplastic tubules of low-grade renal cell carcinomas may be misinterpreted as thickly cut, crushed benign tubules, and the significance of tubulopapillary "adenomas" in frozen sections is unclear. The present report highlights diagnostic difficulties that pathologists may encounter on frozen sections of renal parenchymal margins.     

Feasibility and clinical utility of intraoperative consultation with frozen section in osseous lesions

Intraoperative consultation (IOC) with frozen section (FS) allows the surgeon to make therapy decisions during the operation. However, there is relatively little information on the use of IOC in skeletal lesions. We performed a retrospective study to examine the indications for IOC and compare the histological findings of FS and permanent paraffin section (PS) results to determine its clinical benefits. Ninety-seven consecutive cases evaluated between 2008 and 2011 were retrieved from IOC archives of our Pathology Department. In 79?% of the cases, there was no prior core needle biopsy (CNB), and IOC was performed to confirm the clinical or radiological diagnosis. In 5 (5?%) cases, no definitive result could be obtained with FS, and diagnosis was deferred. The reasons for a deferred diagnosis (DD) included poor section quality in two lipomatous lesions and the sample heterogeneity in the others. When adjusted for DD, FS and PS results showed 100?% concordance in terms of discriminating "benign vs. malignant" and defining diagnostic categories as "benign non-tumoral," "benign tumoral/tumor-like," "malignant primary tumor," "malignant metastatic tumor," or "hematopoietic malignancy." The presence of non-sclerotic osseous tissues does not have a significant adverse impact on the FS section quality and diagnosis made by FS. Thus, sections with diagnostic value can be obtained from bone lesions via FS. In this study, specific diagnoses were made in 88?% of the cases. We believe that IOC with FS can be safely performed in tertiary referral centers where there is a multidisciplinary team working in collaboration.     

Rapid frozen section diagnosis of pituitary tumors

From 751 patients with suspected pituitary tumor, 2,354 frozen sections were prepared for histological identification of the tissue and determination of the resection margins after selective adenoma removal. The accuracy of the method was determined by comparison of the frozen section diagnoses with the diagnoses of permanent sections of the same tissue. The overall accuracy was 83. I%. The reasons for incorrect diagnoses in frozen section were analyzed retrospectively. Prevailing causes were spurious lesions resulting from problems in processing the extremely small specimens, and regressive transformations of the tissue leading to alterations of the tissue structure. Despite the rather low accuracy rate, we would consider frozen section diagnosis of pituitary tumors as a valuable aid for the surgeon. Other morphological methods are not as accurate in the determination of the resection margins in selective microsurgery. If applied by an experienced team, the method can be recommended.     

Accuracy of frozen section diagnosis: a retrospective analysis of 4785 cases

During a 1-year period 4785 intraoperative consultations were performed. The pathology reports were retrospectively reviewed to determine the accuracy of frozen section diagnosis in various tissue types. Skin for evaluation of section margins and axillary sentinel lymph nodes for evaluation of metastatic disease were most frequently sent for frozen section diagnosis. The number of discordant cases were 182, 178 were false negative and four were false positive. When frozen section diagnoses were compared with permanent section diagnoses, the overall diagnostic concordance was 95.1%. The number of deferred specimens was 57. The accuracy of frozen section diagnosis varied between tissue types, and axillary sentinel lymph nodes accounted for the greatest number of discordances. In conclusion, the frozen section diagnosis is a reliable method with varying concordance and deferral rates between tissue types. We suggest regular monitoring of the performance in frozen section diagnosis.     

An evaluation of frozen section biopsy in 4434 cases

Frozen section diagnosis is a highly useful method of diagnosis. There were 4434 frozen sections, 24 false positive diagnosis, 65 false negative diagnosis and 30 deferred diagnosis. This method achieves the highest accuracy when there is a cooperation between experienced surgeon and reliable and careful pathologist. It is wise to defer the diagnosis of consult to other pathologist in difficult situation.     

Accuracy of frozen section measurements for the determination of Breslow tumour thickness in primary malignant melanoma

AIMS: Microstaging of primary malignant melanoma (MM) and the width of surgical margins depend mainly on Breslow tumour thickness (BTT). The use of frozen section (FS) measurements of BTT has been doubted, and previous reports have shown conflicting results regarding the comparability to paraffin sections (PS). To look for significant differences of BTT due to freezing or paraffin embedding, we evaluated a larger series of melanocytic lesions as far as possible excluding other technical influences. METHODS AND RESULTS: Paired 'mirror sections' of 112 melanocytic lesions (33 MM and 79 melanocytic naevi) were measured according to Breslow on single corresponding PS and FS of the same tumour specimen. Comparing measurements on FS and PS, we found very small differences of BTT on average and an almost equal distribution of BTT in the two sets of values with no statistically significant difference by applying the Wilcoxon signed rank test. Concerning the clinically most important 1 mm-threshold of BTT, 110 (98.2%) of the lesions gave equal measurements in FS and PS. CONCLUSIONS: Frozen sections can be used for accurate measurements of Breslow tumour thickness. Consequently, intraoperative frozen section diagnosis of thick melanoma immediately followed by excision with wide surgical margins is possible in experienced centres.     

Intraoperative pathology consultation for pulmonary lesions: errors and deferrals

The accuracy rate of frozen section constitutes an important step of quality assessment step in pathology practice. This study aimed to investigate pulmonary lesions that were incorrectly diagnosed or postponed for routine examination by pathologists at frozen section examination; it also aimed to discuss the reasons for difficult diagnoses and the various clues enabling the correct diagnosis to be made when such lesions are encountered. This study retrospectively reviewed the medical data of the thoracic surgery cases that underwent frozen section examination between 2009 and 2014. Frozen section errors and deferrals were identified in 25 cases. Fourteen (56%) lesions were of pulmonary parenchymal origin and 11 (44%) were of pleural origin. The number of cases in which the pathologists postponed the diagnosis without making any approach was 14. Of these, 9 (64%) were benign lesions such as bronchiectasis, fibrosis anthracosis, chronic inflammatory cell infiltration, chronic pleuritis, and mesothelial proliferation. The number of misdiagnosed cases was 11. Of these, 7 (64%) were of pulmonary and 4 (36%) were of pleural origin. Because the examination techniques of each pathology department may differ from one another, the comparative examination of frozen sections and routine sections would aid in becoming familiar with various pathologies and would be beneficial for pathologists in minimizing their diagnostic errors.