Accuracy and Reproducibility of Frozen Section Diagnosis in Ovarian Tumors: A 10-Year Experience at a Tertiary Cancer Center

Intraoperative frozen section evaluation of ovarian sex cord-stromal tumours and their mimics: a study of 121 cases with emphasis on potential diagnostic pitfalls

Ovarian sex cord-stromal tumours (SCSTs) present diagnostic difficulties during frozen section (FS) consultations due to their diverse morphology. This study aimed to evaluate the accuracy of FS evaluation of SCSTs in our institution, as well as to examine the reasons leading to incorrect FS diagnosis. Cases mimicking SCSTs and diagnosed as such during FS were also highlighted. We analysed 121 ovarian SCST cases and their mimics which underwent FS consultations over a 10-year period, to evaluate FS accuracy, reasons for deferrals and discrepancies. FS diagnoses were concordant, deferred and discrepant compared to the final diagnosis in 50 (41.3%), 39 (32.2%) and 32 (26.5%) cases, respectively. Major discrepancies (9/121, 7.4%) were mostly related to the diagnosis of adult granulosa cell tumour (AGCT). A fibromatous AGCT was misinterpreted as fibroma on FS, while a cystic AGCT was called a benign cyst. Conversely, a mesonephric-like adenocarcinoma, a sertoliform endometrioid carcinoma and a thecoma were misinterpreted as AGCT on FS. Another discrepant case was a Krukenberg tumour with prominent fibromatous stroma in which malignant signet ring cells were overlooked and misinterpreted as fibroma. Minor discrepancies were primarily associated with fibroma (21/23, 91.3%), wherein minor but potentially impactful details such as cellular fibroma and mitotically active cellular fibroma were missed due to sampling issues and misinterpretation as leiomyoma. FS evaluation for ovarian SCSTs demonstrated an overall accuracy of 78.5%, 81.0% and 81.8% for benign, uncertain/low malignant potential and malignant categories, respectively. There was no FS-related adverse clinical impact in all cases with available follow-up information (120/121 cases). Intraoperative FS evaluation of ovarian SCSTs is challenging. A small number of cases were misinterpreted, with AGCTs being the primary group where errors occur. Awareness of common diagnostic pitfalls and difficulties, alongside application of a stepwise approach, including (1) obtaining comprehensive clinical information, (2) thorough macroscopic examination and directed sampling, (3) meticulous microscopic examination with consideration of pitfalls and mimics, (4) effective communication with surgeons in difficult cases, and (5) consultation of subspecialty colleagues in challenging cases, will enhance pathologists' reporting accuracy and management of such cases in the future.

Agreement between frozen section and histopathology to detect malignancy in adnexal masses according to size and morphology by ultrasound

Objective

Management of suspect adnexal masses involves surgery to define the best treatment. Diagnostic choices include a two-stage procedure for histopathology examination (HPE) or intraoperative histological analysis - intraoperative frozen section (IFS) and formalin-fixed and paraffin-soaked tissues (FFPE). Preoperative assessment with ultrasound may also be useful to predict malignancy. We aimed at determining the accuracy of IFS to evaluate adnexal masses stratified by size and morphology having HPE as the diagnostic gold standard.

Methods

A retrospective chart review of 302 patients undergoing IFS of adnexal masses at Hospital de Clínicas de Porto Alegre, between January2005 and September2011 was performed. Data were collected regarding sonographic size (≤10cm or >10cm), characteristics of the lesion, and diagnosis established in IFS and HPE. Eight groups were studied: unilocular lesions; septated/cystic lesions; heterogeneous (solid/cystic) lesions; and solid lesions, divided in two main groups according to the size of lesion, ≤10cm or >10cm. Kappa agreement between IFS and HPE was calculated for each group.

Results

Overall agreement between IFS and HPE was 96.1% for benign tumors, 96.1% for malignant tumors, and 73.3% for borderline tumors. Considering the combination of tumor size and morphology, 100% agreement between IFS and HPE was recorded for unilocular and septated tumors ≤10cm and for solid tumors.

Conclusion

Stratification of adnexal masses according to size and morphology is a good method for preoperative assessment. We should wait for final HPE for staging decision, regardless of IFS results, in heterogeneous adnexal tumors of any size, solid tumors ≤10cm, and all non-solid tumors >10cm.

Neural Network Based Classification of Breast Cancer Histopathological Image from Intraoperative Rapid Frozen Sections

Breast cancer is the leading cause of cancer-related mortality in women worldwide. Despite the rapid developments in diagnostic techniques and medical sciences, pathologic diagnosis is still recognized as the gold standard for disease diagnose. Pathologic diagnosis is a time-consuming task performed for pathologists, needing profound professional knowledge and long-term accumulated diagnostic experience. Therefore, the development of automatic and precise histopathological image classification is essential for medical diagnosis. In this study, an improved VGG network was used to classify the breast cancer histopathological image from intraoperative rapid frozen sections. We adopt a transformed loss function by adding a penalty to cross-entropy in our training stage, which improved the accuracy on test data by 4.39%. Laplacian-4 was used for the enhancement of images, which contributes to the improvement of the accuracy. The accuracy of the proposed model on training data and test data reached 88.70% and 82.27%, respectively, which outperforms the original model by 9.39% of accuracy in test data. The process time was less than 0.25 s per image on average. Meanwhile, the heat maps of predictions were given to show the evidential regions in histopathological images, which could drive improvements in the accuracy, speed, and clinical value of pathological diagnoses. In addition to helping with the actual diagnosis, this technology may be a benefit to pathologists, surgeons, and patients. It might prove to be a helpful tool for pathologists in the future.

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

INTRODUCTION

Pathological 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 METHODS

A 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.

RESULTS

In 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. CONCLUSIONS: This 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.