Feasibility of intraoperative pathologic examination for sentinel lymph nodes during sentinel node navigation surgery in early gastric cancer: results of pathologic protocol for SENORITA trial.

BACKGROUND: During sentinel node navigation surgery in patients with gastric cancer, intraoperative pathologic examination of sentinel nodes is crucial in determining the extent of surgery. In this study, we evaluated the feasibility and accuracy of intraoperative pathologic protocols using data from a prospective, multicenter, randomized trial. METHODS: A retrospective analysis was conducted using data from the SEntinel Node ORIented Tailored Approach trials from 2013 to 2016. All sentinel lymph nodes were evaluated during surgery with hematoxylin-eosin (HE) staining using a representative section at the largest plane for lymph nodes. For permanent histologic evaluation, sentinel basin nodes were stained with HE and cytokeratin immunohistochemistry in formalin-fixed, paraffin-embedded (FFPE) sections and examined with HE for three deeper-step sections at 200-µm intervals. The failure rate of identification by frozen section and the metastasis rate in non-sentinel basins were investigated. RESULTS: Of the 237 patients who underwent sentinel node basin dissection, 30 had lymph node metastases on permanent pathology. Thirteen patients had macrometastasis confirmed in frozen sections as well as FFPE sections (failure rate: 0%). Patients with negative sentinel nodes in frozen sections but micrometastasis in FFPE sections had no lymph node recurrence during the follow-up period (0%, 0/6). However, in cases with tumor-positive nodes in frozen sections, metastases in non-sentinel basins were detected in the paraffin blocks (8.3%, 2/24). CONCLUSIONS: The single-section HE staining method is sufficient for detecting macrometastasis via intraoperative pathological examination. If a negative frozen-section result is confirmed, sentinel basin dissection can be performed safely. Otherwise, standard surgery is required.

Immunofluorescence staining of chloroplast proteins with frozen sections of plant tissues.

KEY MESSAGE: Immunofluorescence staining with frozen sections of plant tissues and a nest tube is convenient and effective, and broadens the applicability of immunofluorescence staining. Immunofluorescence staining is an indispensable and extensively employed technique for determining the subcellular localization of chloroplast division proteins. At present, it is difficult to effectively observe the localization of target proteins in leaves that are hard, or very thin, or have epidermal hair or glands with the current immunofluorescence staining methods. Moreover, signals of target proteins were predominantly detected in mesophyll cells, not the cells of other types. Thus, the method of immunofluorescence staining was further explored for improvement in this study. The plant tissue was embedded with 50% PEG4000 at -60℃, which was then cut into sections by a cryomacrotome. The sections were immediately immersed in fixation solution. Then, the sample was transferred into a special nested plastic tube, which facilitated the fixation and immunofluorescence staining procedures. The use of frozen sections in this method enabled a short processing time and reduced material requirements. By optimizing the thickness of the sections, a large proportion of the cells could be well stained. With this method, we observed the localization of a chloroplast division protein FtsZ1 in the wild-type Arabidopsis and various chloroplast division mutants. Meanwhile, the localization of FtsZ1 was also observed not only in mesophyll cells, but also in guard cells and epidermal cells in a lot of other plant species, including many species with hard leaf tissues. This method is not only easy to use, but also expands the scope of applicability for immunofluorescence staining.

Intraoperative pathologic diagnosis of central nervous system lymphomas: A comparison of frozen and permanent section diagnoses, and the significance of preoperative imaging.

BACKGROUND: Central nervous system (CNS) lymphomas, either primary or secondary in origin, are rare malignant tumors affecting the brain, spinal cord, or leptomeninges. Diagnosis of CNS lymphomas is complicated by their diverse clinical presentations, radiological features, and histopathological characteristics. Although frozen section (FS) analysis is commonly employed for various CNS tumors, its role and accuracy in CNS lymphoma diagnosis are less explored. In this study, we conducted a comparative analysis to assess the impact of knowledge of preoperative imaging on enhancing the accuracy of FS diagnosis in CNS lymphomas. METHODS: Data collection involved a retrospective review of CNS lymphoma patients from January 2009 to August 2021. Patients who underwent intraoperative consultation were included, excluding those with prior cortisone treatment. The dataset incorporated patient demographics, classification as primary or secondary lymphoma, radiological preliminary diagnoses, FS diagnosis, and permanent section diagnosis. We employed various archived materials, including FSs, touch imprint slides, crush cytology slides, H&E-stained sections, and immunohistochemical stains, and re-evaluated all slides for diagnostic validation. RESULTS: Our study included 25 patients, of whom 60 % were female and had a mean age of 56.5 years. Preoperative radiology data were available for 80 % of cases, with preliminary diagnoses commonly including lymphoma and/or metastasis. Intraoperative consultation results indicated lymphoma in 18 (72 %) patients, with discordance observed in 28 % of cases when compared to permanent section diagnoses. Most permanent section diagnoses were diffuse large B-cell lymphomas (92 %), with the remainder being T-cell non-Hodgkin lymphoma (4 %) and follicular lymphoma (4 %). Intraoperative misdiagnoses were significantly associated with the absence of knowledge of preoperative imaging. CONCLUSION: Our study demonstrates the reliability of FS diagnosis for CNS lymphomas during surgery, with a favorable complete concordance rate of 72 % when compared to permanent diagnoses. Importantly, lack of knowledge of preoperative imaging significantly impaired diagnostic accuracy in FS, emphasizing the need for close collaboration between pathologists and radiologists.

Clinical Validation of Stimulated Raman Histology for Rapid Intraoperative Diagnosis of Central Nervous System Tumors.

Stimulated Raman histology (SRH) is an ex vivo optical imaging method that enables microscopic examination of fresh tissue intraoperatively. The conventional intraoperative method uses frozen section analysis, which is labor and time intensive, introduces artifacts that limit diagnostic accuracy, and consumes tissue. SRH imaging allows rapid microscopic imaging of fresh tissue, avoids tissue loss, and enables remote telepathology review. This improves access to expert neuropathology consultation in both low- and high-resource practices. We clinically validated SRH by performing a blinded, retrospective two-arm telepathology study to clinically validate SRH for telepathology at our institution. Using surgical specimens from 47 subjects, we generated a data set composed of 47 SRH images and 47 matched whole slide images (WSIs) of formalin-fixed, paraffin-embedded tissue stained with hematoxylin and eosin, with associated intraoperative clinicoradiologic information and structured diagnostic questions. We compared diagnostic concordance between WSI and SRH-rendered diagnoses. Also, we compared the 1-year median turnaround time (TAT) of intraoperative conventional neuropathology frozen sections with prospectively rendered SRH-telepathology TAT. All SRH images were of sufficient quality for diagnostic review. A review of SRH images showed high accuracy in distinguishing glial from nonglial tumors (96.5% SRH vs 98% WSIs) and predicting final diagnosis (85.9% SRH vs 93.1% WSIs). SRH-based diagnosis and WSI-permanent section diagnosis had high concordance (κ = 0.76). The median TAT for prospectively SRH-rendered diagnosis was 3.7 minutes, approximately 10-fold shorter than the median frozen section TAT (31 minutes). The SRH-imaging procedure did not affect ancillary studies. SRH generates diagnostic virtual histologic images with accuracy comparable to conventional hematoxylin and eosin-based methods in a rapid manner. Our study represents the largest and most rigorous clinical validation of SRH to date. It supports the feasibility of implementing SRH as a rapid method for intraoperative diagnosis complementary to conventional pathology laboratory methods.

Understanding frozen section histopathology in Sinonasal and anterior skull base malignancy and proposed reporting guidelines.

BACKGROUND: Intraoperative frozen section histopathology (IFSH) in sinonasal and skull base surgery although widely used is not well studied. METHODS: We reviewed a database of sinonasal and anterior skull base tumors, between 1973 and 2019, and identified 312 suitable operative cases. Clinicopathologic data was collected and analyzed, in addition to descriptive data for histopathological reports classified as "ambiguous," or "limited/insufficient-quality/quantity." RESULTS: Overall, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for IFSH were 90.2%, 97.5%, 94.2%, 95.6%, and 95.2%, respectively. IFSH for adenocarcinoma, salivary carcinoma, and SCC all demonstrated a better clinical utility with a sensitivity of 90% or greater, while it was less than 90% for esthesioneuroblastoma, melanoma, and sarcoma. Other factors such as unclear reporting, poor quality specimens, or limited quality specimens were shown to lower diagnostic performance. Based on limitations identified, we proposed a novel IFSH reporting algorithm to improve IFSH in sinonasal and skull base surgery. CONCLUSIONS: IFSH is an accurate and clinically useful technique in sinonasal and skull base surgery patients; however, limitations exist.

Utility and diagnostic accuracy of intraoperative frozen sections in hepato-pancreato-biliary surgical pathology.

BACKGROUND AND PURPOSE: Hepato-pancreato-biliary (HPB) surgeries are one of the most challenging and complex procedures. Intraoperative frozen section (IFS) diagnosis plays a pivotal role in management decisions. Comprehensive large cohort studies evaluating utility of IFS in HPB malignancies are lacking. This study aimed to evaluate the accuracy of frozen section analysis and to analyse discrepancies and impact of IFS on the surgical decisions. PATIENTS AND METHODS: This was a retrospective study of IFS received for the HPB specimens between years 2009 and 2021. The results were compared to the permanent sections to evaluate diagnostic accuracy, sensitivity and specificity. Indications, disagreements and impact on the surgical management were analysed. RESULTS: A total of 1008 specimens were evaluated: bile duct margin (279; 27.7%), gallbladder (203; 20.1%), liver lesions (125 cases; 12.4%), lymph nodes (147; 14.6%), pancreatic margin (120; 11.9%) and deposits (134; 13.3%). IFS were diagnosed as negative for malignancy (805; 79.9%), positive for dysplasia (8; 0.8%), suspicious for malignancy (6; 0.6%) and positive for malignancy (189; 18.8%). The overall diagnostic accuracy was 98.4%, and the discordant rate was 1.6%. The sensitivity, specificity, positive predictive value and negative predictive value were 94.7%, 99.4%, 97.5% and 98.6% respectively. The most important reason of discordant results was technical, followed by interpretational and sampling errors. CONCLUSION: The study demonstrates high diagnostic accuracy (98.4%) of IFS in a large dataset of HPB specimens. This comprehensive analysis apprises of the indications, errors and the impact of IFS diagnosis on subsequent HPB surgical management.

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.

[Frozen section biopsy for tumors of the submandibular triangle]. / Schnellschnittdiagnostik bei Tumoren des Trigonum submandibulare.

BACKGROUND: Diagnosis and treatment of submandibular lesions is challenging. Carcinomas, which frequently occur, should be surgically removed with sufficient safety margins, while simultaneously protecting functional structures. In particular, the preservation of neuronal structures with simultaneous tumor control suggests that single-stage concepts are appropriate, although they are not yet established. The aim of this study was to evaluate intraoperative frozen section biopsy as a possible basis for a one-stage surgical concept to thus prevent functional alterations by reoperation. METHODS: A total of 114 consecutive patients with neoplastic lesions in whom the type of lesion could not be determined after ENT examination and imaging were included in the study. Patients with a known history of carcinoma or evidence of an acute inflammatory or carcinogenic primary lesion in the ENT examination and/or imaging were excluded. An intraoperative frozen section biopsy was performed to determine the presence of a carcinoma. Patient-related data and the reliability of the frozen section result were recorded comparatively. RESULTS: Intraoperative frozen section biopsy was performed in a total of 114 patients. Carcinomas were diagnosed with a sensitivity of 87% and a specificity of 100%. There would thus not have been unnecessary radical surgery in a one-stage approach. In 26 of 30 patients with carcinoma, a second operation could have been avoided. CONCLUSION: Intraoperative frozen section biopsy is potentially an important method to histologically confirm carcinomas and avoid two-stage procedures. The absence of false-positive findings would have prevented an unnecessary radical procedure in 100% of patients.

[Value of direct immunohistochemical staining in assisting intraoperative frozen diagnosis of bronchiolar adenoma].

Objective: To explore the feasibility and application value of intraoperative direct immunohistochemical (IHC) staining in improving the diagnosis accuracy in difficult cases of bronchiolar adenoma (BA). Methods: Nineteen cases with single or multiple pulmonary ground-glass nodules or solid nodules indicated by imaging in Cancer Hospital of Chinese Academy of Medical Sciences from January to July 2021 and with difficulty in differential diagnosis at frozen HE sections were selected. In the experimental group, direct IHC staining of cytokeratin 5/6 (CK5/6) and p63 was performed on frozen sections to assist the differentiation of BA from in situ/micro-invasive adenocarcinoma/adenocarcinoma/invasive mucinous adenocarcinoma. In the control group, two pathologists performed routine frozen HE section diagnosis on these 19 cases. The diagnostic results of paraffin sections were used as the gold standard. The sensitivity and specificity of BA diagnosis, consistency with paraffin diagnosis and time used for frozen diagnosis were compared between the experimental group and the control group. Results: The basal cells of BA were highlighted by CK5/6 and p63 staining. There were no basal cells in the in situ/microinvasive adenocarcinoma/adenocarcinoma/invasive mucinous adenocarcinoma. In the experimental group, the sensitivity and specificity with aid of direct IHC staining for BA were 100% and 86.7%, respectively, and the Kappa value of frozen and paraffin diagnosis was 0.732, and these were significantly higher than those in the control group (P<0.05). The average time consumption in the experimental group (32.4 min) was only 7 min longer than that in the control group (25.4 min). Conclusions: Direct IHC staining can improve the accuracy of BA diagnosis intraoperatively and reduce the risk of misdiagnosis, but require significantly longer time. Thus frozen direct IHC staining should be restricted to cases with difficulty in differentiating benign from malignant diseases, especially when the surgical modalities differ based on the frozen diagnosis.

Comparison of Frozen and Permanent Section Diagnosis in Ovarian Neoplasms: Analysis of Factors Affecting Accuracy.

Ovarian cancer is the seventh most common form of cancer among women worldwide. The aim of the study was to determine the accuracy of a frozen section and the factors affecting the accuracy of frozen diagnosis of ovarian neoplasms. This retrospective, cross-sectional study was conducted on 401 patients with ovarian masses with frozen section diagnosis in Shahid Faghihi Hospital affiliated to Shiraz University of Medical Sciences between 2014 and 2018. Each ovarian tumor sample was evaluated for histopathologic diagnosis using frozen and paraffin-embedded sections, which were reviewed by an expert gynecologic pathologist. Accuracy and diagnostic values were estimated by comparing the results of the 2 techniques, using the paraffin section as the gold standard. The overall accuracy of the frozen section was 94.5%. Its sensitivity was 85.3% for malignant, 88.2% for borderline, and 99.6% for benign tumors. Its specificity was also 99.7% for malignant, 98.0% for borderline, and 90.9% for benign tumors. The positive predictive value was 98.9% for malignant, 86.5% for borderline, and 94.6% for benign tumors. Most false negatives occurred in mucinous and borderline tumors. The sensitivity of malignant tumors of germ cell and sex cord-stromal cell types were 64.3% and 95.5%, respectively. The specificity of germ cell and sex-cord stromal tumors were 100% and 93.8%, respectively. Frozen section seems to be a precise technique for histopathologic diagnosis of ovarian tumors. However, borderline and mucinous tumors are the most problematic issues during frozen section diagnosis and malignant germ cell tumors have the lowest sensitivity.

Ovarian tumor frozen section, a multidisciplinary affair.

BACKGROUND: Ovarian Cancer (OC) constitute the eighth most common cancers among women worldwide. Surgery remains the cornerstone in the management of OC. Intraoperative frozen section (FS) diagnosis is widely used to decide the surgery course. We aimed to assess the reliability of intraoperative FS diagnosis for treatment planning of patients with suspected OC from a multidisciplinary perspective. The clinical consequences of reclassification and the multidisciplinary management of the therapy plan, is the secondary aim of this study. To our knowledge, this information is sparely investigated. METHODS: A single-center, retrospective population-based study of patients who underwent surgery for suspected OC between 2018 and 2020. Histopathological outcomes were classified as benign, borderline, or malignant. The FS diagnosis was the diagnostic test, and the final histopathology report was the gold standard. Diagnostic capability for treatment planning was assessed, and modifications made possible by overall clinical knowledge were discussed. RESULTS: A total of 358 patients were identified, of whom 187 were included in the FS group. Overall accuracy was 89.8%, and 19 patients were reclassified; the malignancy grade of 15 tumors was underestimated. Prevalence, sensitivity, specificity, positive predictive value, and negative predictive value for invasive malignancies on FS were 54.0% (CI 46.6-61.3%), 88.1% (CI 80.2-93.7%), 98.8% (CI 93.7-99.9%), 98.9% (CI 92.7-99.8%), and 87.6% (CI 80.6-92.4%), respectively. Tumors incorrectly graded by FS tended to be of borderline-related. CONCLUSIONS: The reliability of the FS methodology was an accurate test to help perform appropriate surgery and plan swift oncological treatment. FS is a reliable method to diagnose invasive malignancies and benign pathology. The communication between the pathologist, surgeon, and medical oncologist is highly important for both intraoperative decision-making and postoperative patient care.

Incomplete Staining Artifact: A Confounding Frozen Section Pathology Artifact Encountered During Mohs Micrographic Surgery.

The intent of this brief communication is to describe a unique incomplete staining frozen section pathology artifact encountered during Mohs Micrographic Surgery. At the authors’ institution, an amorphous, eosinophilic artifact that obscured cellular architecture was observed multiple times during histological interpretation. It was determined that incomplete tissue staining was likely caused by weak staining, possibly related to an interaction between hematoxylin dye solution and acetone. We adjusted our SLS stain line protocol by adding a 15 second water rinse between the acetone and hematoxylin pots and then compared the old fixation protocol with our new fixation protocol. This artifact, which was regularly found intraoperatively at five separate MMS laboratories has sustainably resolved. Mohs Micrographic Surgery (MMS) is a dermatologic procedure that includes tumor extirpation, tissue grossing, slide preparation, and microscopic histologic interpretation. Tissue grossing and slide preparation are vital components of the MMS procedure. There are many steps throughout tissue processing that can result in frozen section pathology artifacts. Frequently encountered frozen section pathology artifacts include vacuolation of cytoplasm or “freeze artifact,” overstaining and understaining with hematoxylin and eosin, incomplete dehydration, and splaying of collagen in the dermis.1-3 We describe a unique incomplete staining frozen section pathology artifact. J Drugs Dermatol. 2022;21(5):542-544. doi:10.36849/JDD.6722.

Frozen Section or Intraoperative Cytology: Are We Ready for a Paradigm Shift in Thoracic Surgery?

Intraoperative frozen sections of specimens taken during thoracic surgery are widely seen as the gold standard. However, the accuracy of intraoperative cytology remains contentious. The study aims to estimate the value of intraoperative cytology by analyzing feasibility, accuracy, time requirements, and possible limitations when compared to standard frozen sections. To this end, we examined a total of 532 intraoperatively harvested specimens out of the 518 resected thoracic tumors from 360 patients between August 2016 and August 2017. The specimens were subject to intraoperative rapid cytology that was later counter compared to the final histology results. The mean time between the intraoperative harvesting and arrival at the laboratory was 2.23 min, and it took a further 3.5 min until the results were communicated to the surgeon. Cytologically, 218 cases (41%) were classified as malignant, 291 (55%) as benign, and 23 (4%) remained unclear. In 55 malignant cases, we observed additional benign formations. The final histological examination performed later yielded 267 malignant and 265 benign cases. Therefore, the sensitivity and specificity of rapid intraoperative cytology were 82% and 99%, respectively, with a negative/positive predictive value of 86%/99%. We conclude that the intraoperative rapid cytology is a fast, accurate, sensitive, and specific procedure for intraoperative decision making and is a distinctly helpful alternative or adjunct for the thoracic surgeon, providing that one is aware of the plausible limitations of this technique.

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.

Is sentinel lymph node biopsy without frozen section in early stage breast cancer sufficient in accordance with ACOSOG-Z0011? A retrospective review from King Chulalongkorn Memorial Hospital.

BACKGROUND: In 2021, there is an increased global trend for sending sentinel lymph node biopsy (SLNB) specimens for permanent section (PS) without intraoperative frozen sections (FS). This pilot study conducted in Thailand determines the re-operation rate for SLNB without FS. METHOD: We retrospectively reviewed 239 SLNB cases without FS at King Chulalongkorn Memorial Hospital from April 2016 to April 2021. The patients were diagnosed with primary invasive breast cancer with clinically negative nodes. The clinical nodal status was assessed from physical examination. The re-operation rate was determined by the number of positive SLNs; where 3 more nodal metastases were subjected to a second surgical procedure. RESULT: Between April 2016 and April 2021, 239 patients who had undergone SLNB in accordance with ACOSOG Z0011 criteria with PS alone was enrolled. A total of 975 SLNs were removed from these 239 patients, with an average of 4.15 nodes per patient. Out of 239 patients, 21 (8.8%) and 6 (2.5%) had metastatic disease in 1 and 2 nodes, respectively. The remaining 212 (88.7%) patients had no nodal metastasis. None of the patients were subjected to a second surgical procedure. CONCLUSION: We conclude that the implementation of SLNB with PS analysis alone in patients who satisfy the ACOSOG Z0011 criteria, with a re-operation rate of 0%, does not have outcomes that would be altered by the standard of care additional FS analysis. With ommision of FS analysis, operation cost, operative time and anesthetic side effects are projected to decrease.

Diagnostic challenges of intra-operative frozen consultation for gastrointestinal signet ring cell carcinoma†.

AIMS: Signet ring cell carcinoma (SRCC) is challenging to recognise on intra-operative frozen sections, with known high false-negative rates. The objective of this study was to investigate common factors contributing to discrepancies between intra-operative frozen diagnoses and those made upon review of permanent sections, and summarise our experiences gained and lessons learned on minimising errors on intra-operative frozen diagnoses of gastrointestinal SRCC. METHODS AND RESULTS: We retrospectively examined our pathology database from 25 May 2000 to 1 January 2018 and re-reviewed intra-operative frozen sections and permanent haematoxylin and eosin (H&E) slides for specimens confirmed with SRCC on permanent sections. This study includes 83 specimens taken from 50 patients, with an accuracy of 85.5%. Main common factors causing discordance or deferral in recognising SRCC between intra-operative frozen procedures and permanent sections include: (i) resemblance of clusters of SRCC cells with a myxoid background; (ii) disguise as normal or reactive cells (histiocytes, macrophages, large reactive lymphocytes, plasma cells or adipocytes) due to their relatively clear or depleted cytoplasmic mucin; and (iii) histological sampling errors, leading to misses of small foci of SRCC on frozen section slides. CONCLUSIONS: An accurate diagnosis of SRCC during intra-operative frozen consultations remains challenging. Based on our experiences and lessons, the most important strategies to reduce diagnostic errors are: (i) understanding the unusual histomorphological features of SRCC cells on frozen sections including, but not limited to, intracellular mucin depletion, absence of desmoplasia and no adjacent pre-cancer changes; and (ii) close attention to abrupt transition from normal architecture (e.g. glandular or submucosal loose connective tissue) to myxoid and/or inflammatory-like appearance, which potentially harbours SRCC.

Diagnostic Accuracy of Intraoperative Frozen Section Analysis in Correlation with Histopathological Diagnosis of Ovarian Tumors in a Tertiary Care Center - A Retrospective Study.

Treatment plan for ovarian neoplasms differs for benign, borderline and malignant tumors. With a turnaround time of 15-20 minutes, frozen section has become a reliable intraoperative diagnostic tool. The aim of this study is to correlate the frozen section diagnosis with subsequent histopathologic diagnosis and determine the accuracy of frozen section diagnosis. The study included 152 ovarian tumors, the overall accuracy of frozen section in diagnosing malignancy was 99.34%, whereas that for benign and borderline tumors were 97.37% and 96.71% respectively. However, the accuracy, sensitivity and specificity for borderline tumors and mucinous tumors were found to be low.

Preoperative endoscopic tattooing using India ink to determine the resection margins during totally laparoscopic distal gastrectomy for gastric cancer.

PURPOSE: This study was conducted to determine whether establishing the proximal resection line using India ink tattooing can ensure safe resection margins during totally laparoscopic distal gastrectomy. METHODS: This retrospective study included 81 patients who underwent totally laparoscopic distal gastrectomy for gastric cancer on the lower two-thirds of the stomach. The proximal resection margins were analyzed with respect to the macroscopic type and clinical T stage, and the intraoperative appearance of the stain on the serosa was classified by reviewing surgical videos. RESULTS: R0 resection was performed in all patients. The rates of the intended margins were 89.2% in patients without a frozen section diagnosis and 84.2% in patients with differentiated type lesions who underwent a frozen section diagnosis; however, most patients with undifferentiated advanced lesions failed to achieve the intended resection margins. Intraoperative appearance revealed that 85.2% of patients had localized type stains, whereas 11.1% had widespread-type stains. CONCLUSIONS: Our procedure to determine the proximal resection line in totally laparoscopic distal gastrectomy is oncologically safe. However, careful observation of the resected specimen and a frozen section analysis should be performed for undifferentiated advanced lesions.

The utility of intraoperative retroareolar margin frozen section assessment and the management of atypical epithelial proliferative lesions at the retroareolar margin in nipple-sparing mastectomies.

OBJECTIVES: Nipple-sparing mastectomy (NSM) has become more frequently utilized due to superior psychological and cosmetic outcomes. The aim of this study was to evaluate the accuracy and utility of intraoperative frozen section evaluation of the retroareolar margin (RAM) in NSM. The management of atypical epithelial proliferative lesions at the RAM was also reviewed and discussed. METHODS: A single institution, retrospective analysis was performed on all therapeutic NSM patients with intraoperative evaluation of the RAM from 2014 to 2018. Patient demographics, tumor characteristics, pathologic assessment of the RAM, surgical management, and clinical follow-up were reviewed. RESULTS: Seventy-four nipple-sparing mastectomies with intraoperative evaluation of RAMs were identified. Concordance was 95% between frozen and permanent section diagnoses with 4 cases representing false negatives and no false positives. There were no instances of nipple-areolar complex (NAC) recurrence in all cases with preserved NACs (mean follow up: 750 days). In the 9 cases where NACs were excised based on intraoperative RAM evaluation, the findings in the excised NACs were negative in 6 and ductal carcinoma in situ in 3 cases. Postoperative measurement of the tumor to nipple distance was the only statistically significant variable associated with a positive RAM by multivariable logistic regression (OR 0.475; 95% CI 0.238-0.946). CONCLUSIONS: Intraoperative RAM evaluation demonstrated high concordance with permanent histology. Negative RAM, including atypical epithelial proliferative lesions, led to NAC preservation without recurrence. Positive RAM alone did not predict NAC involvement, although pagetoid spread of ductal carcinoma in situ along nipple ducts may predict NAC positivity.

Frozen-section examination in the management of paediatric testicular lesions.

PURPOSE: Paediatric testicular and para-testicular lesions have traditionally been managed according to adult protocols. Testis-sparing surgery (TSS) has gained popularity as it has become apparent benign lesions predominate in childhood. Frozen-section examination (FSE) for intra-operative diagnosis has been extensively utilised in adults, though its use in paediatric practice remains limited. We reviewed our experience of FSE in paediatric patients with an aim to identify the utility and efficacy of this tool in the management of testicular and para-testicular pathology. METHODS: A retrospective, single-centre review of paediatric patients who underwent intra-operative FSE for a range of testicular and para-testicular lesions was performed. FSE results were compared to final pathology. TSS was performed if appropriate, and was utilised in adolescent patients, and in lesions with a diameter greater than 20 mm. RESULTS: Nine males underwent FSE from 2013 to 2020. Median age at surgery was 9 years (range 1-15). Eight (89%) patients had benign pathology. FSE result correlated with the final pathological examination in 100% of cases. FSE facilitated TSS in 7/9 cases. CONCLUSION: FSE has 100% diagnostic accuracy for paediatric testicular and para-testicular pathology. We would recommend all lesions be evaluated by FSE to guide intra-operative decision making and facilitate TSS in appropriate cases.