FNAC as preoperative diagnostic tool for neoplastic and non-neoplastic breast lesions with special reference to IAC standardised reporting in Coastal population - A teaching hospital experience

Introduction: Breast cancer affects 2.1 million women each year and is the most common cancer among females, followed by lung, colorectum, uterus, and cervix. Breast cancer accounted for 6,26,679 (6.6%) deaths in 2018. Breast cancer incidence is on the rise in every part of the globe, including developed countries. Fine Needle Aspiration Cytology (FNAC) shows high sensitivity, specificity, and accuracy in evaluation of breast lesions. FNAC is part of the triple test and is the gold standard for assessment. The new reporting system for breast FNAC, proposed by the International Academy of Cytology (IAC) Yokohama Breast Cytopathology System, has standardised the reporting system to categorise breast lesions and as unmasked the diagnostic dilemma faced by reporting cytopathologist. Aim: The study aimed to categorise the samples according to IAC Yokohama Breast Cytopathology System and assess the Risk of Malignancy (ROM) for each category and increase the diagnostic yield of breast FNAC. Materials and Methods: A retrospective cohort study included 1,467 breast FNAC cases, which were retrieved and reclassified based on the newly proposed IAC Yokohama System into five categories during January 2017-December 2018 in Kidwai Memorial Institute of Oncology (KMIO), Bangalore. Histopathology correlation was done, and the Risk of Malignancy (ROM) was assessed whenever possible. The study results were analysed using Microsoft excel 2007, sensitivity, specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV), and accuracy ratios were calculated using the MedCalc diagnostic test evaluation calculator, keeping histologic diagnosis as the gold standard. Results: Re-categorisation of 1,467 cases was done according to the Yokohama breast cytopathology system as insufficient material, benign, atypical, suspicious for malignancy, and malignant. The histopathology diagnosis was available in 1,069 cases. The respective ROM for each category was, 7.6% for category 1 (Insufficient), 15.26% for category 2 (Benign), 65.38% for category 3 (Atypical), 83.33% for category 4 (Suspicious) and 99.18% for category 5 (Malignant). Considering malignant cases as positive, sensitivity-86.75%, specificity-97.32%, PPV-99.19%, NPV-66.06% and accuracy of 88.96% was deduced. Conclusion: It is recommended to incorporate the IAC Yokohama system to categorise breast cytopathology with uniform terminologies. This will help diagnose breast lesions more consistently and accurately, which in turn helps the clinician manage the disease and predict the ROM and the patient outcome.

BackgroundFine-needle aspiration cytology (FNAC) of the breast is a well-established technique that aids in the preoperative identification and differentiation between nonneoplastic and neoplastic breast lesions. Breast lesions can be efficiently categorized into different cytological groups using the International Academy of Cytology (IAC) Yokohama System. The aim of this study was to classify breast lesions based on the proposed Yokohama system of reporting breast cytology and identify the need for a unified system of reporting breast lesions.Materials and methodsThis retrospective descriptive study was performed in the Department of Pathology, Government Medical College, Datia, M.P. from January 2019 to June 2023. A total of 762 FNAC slides reported during this period were retrieved, re-examined and reclassified according to the IAC Yokohama System. Histopathological diagnoses were also retrieved and correlated with the cytological findings wherever available.ResultsIn the present study, a total of 762 smears of breast fine needle aspirations were included and categorized using the IAC Yokohama System. There were 3.8% cases (29/762) in the C1 category (insufficient), 71.6% cases (545/762) in the C2 category (benign), 6.3% cases (48/762) in the C3 category (atypical), 3.1% cases (24/762) in the C4 category (suspicious for malignancy) and 15.2% (116/762) cases in the C5 category (malignant).ConclusionFNAC is a reliable diagnostic technique for the evaluation and management of breast lesions prior to surgery. Implementing the IAC Yokohama System for reporting breast cytopathology enhances the accuracy of diagnosing breast lesions, reduces missed diagnoses, and offers reliable estimates of risk of malignancy. Adopting the Yokohama system is a crucial first step in boosting the overall effectiveness of breast cytology reporting among clinicians and pathologists, which will ultimately lead to improved communication and patient care.

Introduction: Fine Needle Aspiration Cytology (FNAC) is a rapid, minimally invasive and cost-effective procedure with a high sensitivity rate of 92-95% and high Positive Predictive Value (PPV) approaching 100% for the diagnosis of breast malignancies. International Academy of Cytology (IAC) Yokohama system for reporting breast FNACs had been established in 2016 to bring consistency and uniformity of breast cytology reporting. Aim: To classify the breast lesions according to the IAC Yokohama system for cytological reporting of breast lesions. Materials and Methods: This was a retrospective six years study carried out in the Department of Pathology, Karpaga Vinayaga Institute of Medical Sciences, Chinnakolambakkam, Tamil Nadu, India. All females breast FNAC cases reported during the year January 2015 to December 2020 were included in the study according to the inclusion criteria. Relevant clinical and pathological data including the FNAC reports were retrieved from the medical records of the department. Corresponding FNAC smears stained with Haematoxylin and Eosin (H&E) and Papanicolaou stains were reviewed and double-checked with the FNAC reports. All those cases were grouped according to the IAC Yokohama System. Statistical analysis was carried out using Statistical Package for the Social Sciences (SPSS) version 23.0. Results: Of the total 381 female breast FNACs, majority (60%) of them belonged to the age group of 21-40 years. The predominant presenting symptom was palpable breast lump (73%) and Upper Outer Quadrant (UOQ) was involved in 65% of cases. Out of 381 cases, 297 (78%) were benign, 52 (13.6%) were malignant and 32 (8.4%) were inadequate for diagnosis. Total 73.8% cases belonged to “C2” category and fibroadenoma was the most prevalent lesion. Pearson Chi-square test showed highly significant association between patient’s age above 40 years and the risk of having a malignant breast lesion (p<0.0001). Conclusion: FNAC is an effective diagnostic modality for preoperative diagnosis of breast lesions thereby facilitating proper treatment at an early stage of the disease. Also adherence to the standardised cytological reporting system like IAC Yokohama system will ensure quality assurance across various institutions, thereby strengthening the healthcare services.

BackgroundPalpable breast lump, breast pain, and nipple discharge are common symptoms of breast disease. Breast cytology (fine-needle aspiration, nipple discharge smear, and touch preparation) accurately identifies benign, atypical, and malignant pathological changes in breast specimens. This study aims to determine the types of breast lesions diagnosed by breast cytology and assess the clinical adequacy of narrative reporting of breast cytology results.MethodsMedical records of 390 patients presenting to breast or general surgery clinics in Kenyatta National Hospital, Nairobi, Kenya, between January 2010 and March 2014 were evaluated retrospectively.ResultsOf the 390 diagnosed breast lesions, 89.7 % (n = 350) occurred in females, while 10.3 % (n = 40) occurred in males, giving rise to a female-to-male ratio of 8.8:1. Neoplastic breast lesions (n = 296) comprised 75.9 %, while non-neoplastic breast lesions (n = 94) comprised 24.1 % of all diagnosed breast lesions. The neoplastic lesions were classified as 72.3 % (n = 214) benign and 27.7 % (n = 82) malignant, resulting in a benign-to-malignant ratio of 2.6:1. Fibroadenoma (n = 136) and gynecomastia (n = 33) were the most frequently diagnosed breast lesions for women and men, respectively.ConclusionsBreast cytology effectively diagnosed neoplastic and non-neoplastic breast lesions. Neoplastic breast lesions occurred more frequently in women whereas non-neoplastic lesions occurred more frequently in men. To address the limitations associated with narrative reporting of breast cytology results, a synoptic reporting format incorporating the United Kingdom’s National Health Service Breast Screening Programme’s diagnostic categories (C1 to C5) is recommended for adoption by this hospital.

Background:International Academy of Cytology (IAC) has established a process to produce comprehensive and standardized approach to fine-needle aspiration cytology (FNAC) reporting. They have categorized the breast lesions in C1 to C5. (C1-Insufficient material, C2-Benign, C3- Atypical, C4-Suspicious & C5-Malignant).Aims and Objectives:The aim of study is to classify various breast lesions (C1 to C5) and to grade breast carcinoma on FNAC using Robinson's grading system which is then correlated with modified Bloom–Richardson grading.Materials and Methods:All routine FNAC for breast lump were included in the study during the period from Jan 2016 to Jan 2017. The study was conducted in the Department of pathology and lab medicine of a tertiary care hospital in central India.Results:A total 225 female patients were included in the study, with an age group ranging from 15 - 79 years, with lesions in breast were taken. C1 lesions were found in 3 cases, C2 in 186 cases, C3 in 13 cases, C4 in 4 cases, and C5 in 19 cases. Correlation of cytohistological grading was obtained in 108 cases.Conclusion:Cytological categorization based on IAC structured reporting will enhance the reproducibility of reports among pathologist & clinicians. With the comparison between cytohistological nuclear grading, the cytoprognostic scores will help in evaluating the aggressiveness of tumor, predicts histological grade and prognosis. It could be a useful parameter for selecting neo-adjuvant chemotherapy.

Recently the International Academy of Cytology (IAC) introduced a new reporting system for breast fine-needle aspiration cytology that classifies cytologic diagnoses into five-categories: (I) insufficient material, (II) benign, (III) atypical, (IV) suspicious of malignancy, and (V) malignant. The current study was undertaken to categorize the breast lesions utilizing the newly proposed IAC Yokohama classification system and evaluate the risk of malignancy (ROM) for respective categories and the diagnostic yield of this technique. All FNAs of breast lesions over 2.5 years were categorized retrospectively using the newly proposed IAC Yokohama reporting system. The ROM was calculated along with sensitivity, specificity, positive and negative predictive value, diagnostic accuracy, false positive, and false-negative rate using the histological diagnosis as the gold standard. The 512 cases were distributed as follows: Category I (insufficient material) 7.4%, Category II (benign) 74%, Category III (atypical) 5.7%, Category IV(suspicious) 1.4%, and Category V (malignant) 11.5%. Histopathological correlation was available in 285 (55.7%) cases. The respective ROM calculated was 33.3%, 0.5%, 13.3%, 83.3%, and 100% for Category I-V. The Sensitivity, Specificity, Positive and Negative Predictive Value, and Diagnostic accuracy were 95%, 99.5%, 98.27%, 98.6, and 98.5% respectively. Despite previous attempts to establish a standardized diagnostic terminology, there has been a lack of a single internationally approved standardized reporting system allowing substantial diagnostic clarity and incorporating distinct diagnostic categories, each linked with a specific ROM and recommended management. This System also provides enhanced communication between pathologists and attending clinicians for the benefit of the patient.

Introduction: Breast cancer is rapidly emerging as the leading cause of cancer in Indian women. Cytopathology and histopathology services are required to tackle this growing burden. The use of International Academy of Cytology (IAC) Yokohama Reporting System of breast cytology by classifying them into five categories insufficient, benign, atypical, suspicious and malignant. (IAC) Yokohama Reporting System offers structured protocols, are expected to improve breast cytopathology reporting. Objective : The main objectives of our study were to classify breast fine needle aspirates according to the IAC Yokohama system and assess the risk of malignancy, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy. Methodology: All breast FNAs done in the above period were retrieved and classified into five categories according to the Yokohama system. Histopathological diagnosis was also retrieved wherever available. Results: The new “International Academy of Cytology (IAC) Yokohama system” was used to categorize 205 patients into five categories based on the cytologic diagnosis. That C1: insucient material (7.8%), C2: benign (64.3%), C3: atypical (7.3%), C4: suspicious of malignancy (7.8%), and C5: malignant (12.6%). Risk of malignancy (ROM) was calculated which was 100% in Yokohama category I, IV and V. In category II ROM was 00% and in category III ROM was 55.5%. FNAC correlation with histopathology was significant (P Value=<0.01 & Chi square value 40.7). Conclusion: The IAC Yokohama system is an excellent system for accurately diagnosing breast fine needle aspirate. Keywords: Histopathology, International Academy of Cytology Yokohama System, Fine­ Needle Aspiration Biopsy Cytopathology

The International Academy of Cytology (IAC) Yokohama System has developed a standardized system of reporting breast cytology. The current study aimed to apply the newly proposed YOKOHAMA classification system along with American College of Radiology Breast Imaging Reporting and Data system (ACR-BI-RADS) scoring to breast fine-needle aspiration cytology (FNAC) cases from the department archives and to assess the risk of malignancy (ROM) for each category. All breast FNACs done between January 20017 and June 2023 were reclassified according to the proposed IAC Yokohama reporting system. Histopathological correlation of the IAC Yokohama system and BI-RADS was done wherever available. A three-category approach was followed based on benign versus malignant, and sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy were calculated using histopathology as the gold standard. A total of 2130 breast FNACs were performed, of which 469 had a histopathological correlation and 892 had a BI-RADS correlation. The ROM for insufficient, benign, atypical, suspicious, and malignant categories were 29.16%, 3.28%, 28.57%, 100%, and 92.18%, respectively. Maximum specificity (96.8%) was observed when only malignant (cat A) and when both suspicious and malignant cases (Cat B) were taken as positive test results. Highest sensitivity (92.7%) was achieved when atypical, suspicious, and malignant cases were taken as positive test results (Cat C) and highest diagnostic accuracy (94.8%) was seen in category B. The sensitivity, specificity, PPV, NPV, and diagnostic accuracy of BI-ADS were 78.67%, 92%, 85.5%, 87.8%, and 87%, respectively. FNAC and imaging are the key modalities for diagnosing breast lesions. The IAC Yokohama system along with ACR-BI-RADS provides a simple yet useful approach for effectively categorizing the different breast lesions, which is useful for patient management and risk stratification.

Context: International academy of cytology (IAC) has established a standardized reporting system for fine-needle aspiration (FNA) cytology of breast lesions. They have introduced five categories (Code C1 to Code C5) for reporting breast cytology, each with clear descriptive term for the category, risk of malignancy (ROM) and a suggested management algorithm. Aim: Aims of the present study were to reclassify and correlate the breast FNA (IAC guidelines) with histopathological findings and to calculate the ROM for each category with special emphasis on assessing the diagnostic efficacy of cytological evaluation of code 3 and code 4. Materials and Methods: A 3 years' retrospective cross sectional study included 448 breast FNA samples that were reassessed and reclassified according to the IAC reporting system. The ROM for each category was analyzed. Results: The breast FNA samples were distributed in following categories as: C1 (insufficient material)− 1.78% (n = 8), C2 (benign) – 71.66% (n = 321), C3 (Atypical but benign) −10.81% (n = 45), C4 (Suspicious for malignancy) – 4.91% (n = 22), and C5 (Malignant)– 11.60% (n = 52). Out of the 448 cases, histopathological correlation was available for 205 cases. The ROM for each category was calculated as: 0% for C1, 2.04% for C2, 10.8% for C3, 85.71% for C4, and 100% for C5. The ability of C3 and C4 lesions to diagnose breast malignancy was statistically significant, P value 0.042 (P < 0.05). Conclusion: The IAC system for reporting of breast cytology effectively helps in accurate diagnosis and assessment of ROM for each category which helps in better patient management and further research.

BackgroundThe International Academy of Cytology (I.A.C.) Yokohama System to report breast cytopathology can effectively categorize breast diseases into different cytological groups. Fine needle aspiration (FNAC) from the lesions in the breast has been regarded as a major method of diagnosing breast cancer, particularly in rural settings. The major purpose of this study was to validate the diagnostic accuracy of breast FNA utilizing the IAC Yokohama system in future endurances. Histopathological examination is considered the gold standard for diagnosing benign as well as malignant breast lesions and is compared with FNA results.Material and methodsResearch on patients getting a core-needle, incisional, or excisional biopsy of breast lesions between January 1st, 2021, and December 31st, 2021, was conducted at a tertiary care center in central India. 216 breast FNAs were recorded utilizing the IAC Yokohama system, and the most appropriate category was assigned for every case and correlated with histopathology to evaluate the effectiveness of IAC system.ResultsThe new "International Academy of Cytology (IAC) Yokohama system" was used to categorize 216 patients into five categories based on the cytologic diagnosis.Those were C1: insufficient material (8.7%), C2: benign (65.7%), C3: atypical (1.8%), C4: suspicious of malignancy (2.7%), and C5: malignant (20.8%). FNACs were associated with ancillary testing and histological diagnosis to examine diagnostic accuracy. The overall Specificity, sensitivity, negative predictive value, positive predictive value, and accuracy were calculated with the risk of malignancy.ConclusionWith high specificity and sensitivity for each type of situation, for all tumors, and for each analyzed BI-RADS category, the IAC Yokohama system provides excellent accuracy for breast FNA .

Background and Objective: The International Academy of Cytology (IAC) Yokohama system for reporting breast fine-needle aspiration biopsy (FNAB) cytopathology has been proposed to standardize breast FNAB reporting. The aim of this study was to categorize breast FNAB cases performed by palpation without radiological guidance according to the IAC system, establish the risk of malignancy (ROM) for the categories and assess the system’s utility, pitfalls, and implications in low-resource/financial constraint settings. Methods: A retrospective analysis of palpation-guided FNAB of breast lesions performed without radiological guidance between January 2016 and December 2019 was carried out and was correlated with follow-up biopsies wherever available. A total of 1,089 cases were recategorized using the IAC Yokohama system. Histopathology follow-up was available for 400 cases. The data were analysed for ROM, positive predictive value (PPV), and negative predictive value (NPV). Results and Discussion: Out of 1,089 cases, 4.3% (n = 47) cases were categorized as insufficient, 82% (n = 893) as benign, 2.8% (n = 31) as atypical, 2.7% (n = 29) as suspicious of malignancy, and 8.2% (n = 89) as malignant. Some 400 cases had a follow-up biopsy, based on which, the ROM for the categories were 33.3%, 0.4%, 37.5%, 96%, and 100%. The NPV for the benign category was 99.6%. The PPV of the malignant category was 100%, that of combined suspicious of malignancy and malignant categories was 99%, and of combined atypical, suspicious of malignancy, and malignant was 90.6%. Conclusion: The IAC Yokohama system is useful in standardizing the reporting of cytopathology of breast lesions. FNAB with radiological guidance is ideal but in cases of finance/resource constraints, FNAB by palpation alone is satisfactory if the test result is in the benign, suspicious of malignancy, or malignant categories, which constitute 91.5% of the cases in this study. A repeat ultrasound-guided FNAB and/or core needle biopsy should be recommended for cases in the insufficient/inadequate or atypical categories.

Background: Benign and malignant lesions of breast are one of the most common causes of palpable masses seen in women. Fine-needle aspiration cytology (FNAC) is the important modality of diagnosis of breast lumps. Previously, there were no uniform criteria for reporting breast FNAC. To overcome this problem, the newly designed system – International Academy of Cytology (IAC) – Yokohama system of reporting was implemented in 2016. The system offers a structured report to the patient. Aims and Objectives: This study aims to categorize breast FNAC according to the IAC – Yokohama system of reporting, to calculate the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy of the test, and to analyze the cytomorphological spectrum of various breast lesions. Materials and Methods: A total of 210 patients presenting with breast lump in cytology section were subjected to FNAC using a 22 gauge needle under all aseptic precautions. Detailed clinical history was taken. All cytology and histopathology examination slides (wherever available) were thoroughly studied. FNAC smears were reported using IAC – Yokohama system of reporting. Results: In our study, benign category (C2) was most commonly seen in 73.33% of cases, followed by 10.48% of cases of atypical probably benign (C3), 2.38% of cases were reported as suspicious (C4), and 11.43% of cases were reported as malignant (C5). Cytohistopathological concordance was seen in 38 cases (88.4%) whereas five cases were reported as discordant. Sensitivity and specificity of the test for the diagnosis of malignancy were 81% and 100%, respectively. PPV was 100%. NPV was 90.90%. Diagnostic accuracy of the test was 93.47%. Conclusion: The newer IAC – Yokohama system of reporting of breast FNAC is simple, has clear diagnostic criteria hence boost up the confidence as well has uniformity of reporting by cytopathologist, and increases the understanding and uniformity in assessment by the attending clinician which help in improving the communication between the pathologist and the treating clinician.

Background: Benign and malignant lesions of breast are one of the most common causes of palpable masses seen in women. Fine-needle aspiration cytology (FNAC) is the important modality of diagnosis of breast lumps. Previously, there were no uniform criteria for reporting breast FNAC. To overcome this problem, the newly designed system – International Academy of Cytology (IAC) – Yokohama system of reporting was implemented in 2016. The system offers a structured report to the patient. Aims and Objectives: This study aims to categorize breast FNAC according to the IAC – Yokohama system of reporting, to calculate the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy of the test, and to analyze the cytomorphological spectrum of various breast lesions. Materials and Methods: A total of 210 patients presenting with breast lump in cytology section were subjected to FNAC using a 22 gauge needle under all aseptic precautions. Detailed clinical history was taken. All cytology and histopathology examination slides (wherever available) were thoroughly studied. FNAC smears were reported using IAC – Yokohama system of reporting. Results: In our study, benign category (C2) was most commonly seen in 73.33% of cases, followed by 10.48% of cases of atypical probably benign (C3), 2.38% of cases were reported as suspicious (C4), and 11.43% of cases were reported as malignant (C5). Cytohistopathological concordance was seen in 38 cases (88.4%) whereas five cases were reported as discordant. Sensitivity and specificity of the test for the diagnosis of malignancy were 81% and 100%, respectively. PPV was 100%. NPV was 90.90%. Diagnostic accuracy of the test was 93.47%. Conclusion: The newer IAC – Yokohama system of reporting of breast FNAC is simple, has clear diagnostic criteria hence boost up the confidence as well has uniformity of reporting by cytopathologist, and increases the understanding and uniformity in assessment by the attending clinician which help in improving the communication between the pathologist and the treating clinician.

Introduction: Breast cancer is rapidly emerging as the leading cause of cancer in Indian women. Robust cytopathology and histopathology services are required to tackle this growing burden. The use of rapid on-site evaluation (ROSE) and the International Academy of Cytology (IAC) Yokohama System for Reporting Breast Fine-Needle Aspiration Biopsy (FNAB) Cytopathology, which offers structured protocols, are expected to improve breast cytopathology reporting. Methods: We retrieved the cytopathology slides, categorized them by the IAC Yokohama System and histopathology data of all the patients who had been investigated for breast lesions from September 2016 to December 2018, and compared the cytopathology and histopathology. Risk of malignancy (ROM) and performance metrics, like sensitivity, specificity, predictive values, accuracy, and area under the curve were computed. Results: A total of 1,147 FNABs were evaluated, of which 442 (38.5%) underwent ROSE and 624 (54.4%) histopathology. Reported using IAC categories, our cohort recorded 4.9% inadequate, 65.3% benign, 7.8% atypical, 3.3% suspicious for malignancy, and 18.7% malignant lesions. The overall sensitivity and specificity for identifying in situ and malignant lesions were 99.1% and 99.3%, respectively, and were substantially improved by ROSE. ROSE improved the concordance between cytopathology and histopathology from 76.9% to 90.2%, by reducing inadequate (p < 0.001) cases. The ROM increased along a gradient from inadequate to malignant categories, with the gradient being sharpened by ROSE. The false negativity rate was 0.7% and false positivity rate 0%. Conclusion: Incorporating ROSE and the IAC Yokohama System for breast cytopathology reporting improves accurate diagnosis of breast lesions, prevents missed diagnoses, and provides reliable estimates of ROM. These protocols also aid in standardizing a reproducible system for monitoring and auditing of breast pathology services, identify areas that need strengthening, and improve training at pathology centers.

Background: Breast lumps pose a significant health concern globally, contributing to both illness and death. The International Academy of Cytology (IAC) Yokohama system has established a uniform method for reporting breast cytology, categorizing it into five groups: inadequate, benign, atypical, suspicious, and malignant. Aims and Objectives: This study primarily aimed to evaluate breast lesions using the IAC Yokohama System and compare the results with those of corresponding histopathological biopsies. Additionally, the study aimed to analyze the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and diagnostic accuracy of breast fine-needle aspiration cytology (FNAC) and determine the risk of malignancy associated with each category. Materials and Methods: In this study, 92 cases were analyzed and categorized according to the IAC Yokohama System. Sensitivity, specificity, PPV, NPV, diagnostic accuracy, and risk of malignancy were determined based on histopathological diagnosis, which was considered the reference standard. Results: Among the 92 breast FNACs, the risk of malignancy for the categories insufficient, benign, atypical, suspicious, and malignant were 0%, 0%, 18.75%, 100%, and 100%, respectively. The highest sensitivity (100%) was achieved when considering atypical, suspicious, and malignant cases as positive results. The specificity was highest (100%) when only malignant or both malignant and suspicious cases were considered positive results. The highest diagnostic accuracy (95.65%) was observed when including malignant and suspicious cases as positive results. Conclusion: Implementing the IAC Yokohama System for reporting breast cytopathology through structured reporting will enhance the quality, clarity, and reproducibility of reports among pathologists and clinicians, which would result in enhanced patient care and management.