FREQUENCY OF DIAGNOSTIC CONCORDANCE IN CORE BREAST BIOPSIES OF CATEGORY B3 AND B4 AT A TERTIARY CARE CENTRE

ABSTRACT Objective: To evaluate interobserver variability in core breast biopsies of category B3 and B4 at a tertiary care centre Study Design: Retrospective, observational, cross-sectional study. Place and Duration of Study: Histopathology Department, Armed Forces Institute of Pathology (AFIP), Rawalpindi, from Mar 2017 to Jun 2018. Methodology: A total of thirty cases of histologically confirmed lesions of category B3 and B4 on core breast biopsies from March 2017 to June 2018 were retrieved from archive of Histopathology department, AFIP Rawalpindi. Patients' age, histologic diagnosis and reporting B category were noted. The selected cases were anonymized and distributed among 3 pathologists for independent review. The participating pathologists were kept unaware of the findings given by fellow participants and previously agreed reference diagnoses. Study cases were reviewed by the participating pathologists. The results were analyzed and overall concordance rate, discordance rate, over interpretation rate and under interpretation rate were calculated. Results: A total of 30 (n = 30) patients were enrolled of which 22 were assigned category B3 (73%) and 8 were assigned category B4 (27%) on initial microscopic evaluation (original opinion). The ages of the study patients ranged from 25 to 85 years. The average concordance rate of morphologic findings of study pathologists compared to the reference diagnosis was 63% (19/30). Among these the average concordance rate compared to reference diagnosis among category B3 lesions was 73% (16/22) and among category B4 lesions was 37.5% (3/8). The average rate of disagreement of morphologic findings of study pathologists compared with the reference diagnosis was 37% (11/30). Among these the average rate of disagreement compared to reference diagnosis among category B3 lesions 27% (6/22) and among category B4 lesions was 62.5% (5/8). The overall over interpretation rate was 44% and overall under interpretation rate was 56%. The overall rate of unanimous agreement of independent diagnoses among the three panel consultants was 50% (15/30). Among these 15 cases 12 were assigned category B3 and 3 were assigned category B4. The overall rate of disagreement of independent diagnoses among the three panel consultants was 50% (15/30). Conclusion: In our study the opinion was established by interpretation of a single slide. Average concordance rate among the participating pathologists' findings and the previously agreed upon