Quality assurance in breast pathology: Lessons learned from a review of amended reports

Context.-A review of amended pathology reports provides valuable information regarding defects in the surgical pathology process. Objective.-To review amended breast pathology reports with emphasis placed on interpretative errors and their mechanisms of detection. Design.-All amended pathology reports for breast surgical specimens for a 5-year period at a large academic medical center were retrospectively identified and classified based on an established taxonomy. Results.-Of 12 228 breast pathology reports, 122 amended reports were identified. Most (88 cases; 72%) amendments were due to noninterpretative errors, including 58 report defects, 12 misidentifications, and 3 specimen defects. A few (34 cases; 27.9%) were classified as misinterpretations, including 14 major diagnostic changes (11.5% of all amendments). Among major changes, there were cases of missed microinvasion or small foci of invasion, missed micrometastasis, atypical ductal hyperplasia overcalled as ductal carcinoma in situ, ductal carcinoma in situ involving sclerosing adenosis mistaken for invasive carcinoma, lymphoma mistaken for invasive carcinoma, and amyloidosis misdiagnosed as fat necrosis. Nine major changes were detected at interpretation of receptor studies and were not associated with clinical consequences. Three cases were associated with clinical consequences, and of note, the same pathologist interpreted the corresponding receptor studies. Conclusions.-Review of amended reports was a useful method for identifying error frequencies, types, and methods of detection. Any time that a case is revisited for ancillary studies or other reasons, it is an opportunity for the surgical pathologist to reconsider one's own or another's diagnosis.