The changing presentation of carcinoma of the breast and its impact on the reliability of the frozen section diagnosis

To determine the impact of earlier clinical detection of breast carcinoma on the reliability of its frozen section diagnosis, we undertook a study of 696 breast biopsy frozen sections consisting of two consecutive series, one in 1982 - 1983 and the other in 1986 - 1988. The overall accuracy rate in the entire series was 95.8%, whereas the accuracy rate in the diagnosis of 36 cases of duct carcinoma in situ was 36.1%. This is comparable to two previous similar series in which the accuracy rate was 26.9% and 34% respectively. The diagnosis of DCIS was missed at the time of frozen section in 23 cases. Errors of selection accounted for 16 (69.6%) of the 23 cases and errors of interpretation accounted for 7 cases (30.4%). Almost all missed diagnoses were justifiable and unavoidable. We conclude that the frozen section is not a reliable method for the diagnosis of in situ duct carcinoma and its differentiation from benign borderline lesions. The goal of the frozen section in these early breast lesions is the detection of an infiltrating carcinoma. This is done by meticulous gross examination with specimen radiography. Microscopic examination with frozen section is to be done if a distinct tumor is detected, to confirm an in vasive carcinoma and procure tissue for hormone receptor analysis. If no distinct tumor is detected, it is more appropriate to relegate microscopic examination to paraffin sections, which allow better assessment of these borderline lesions.