Abstract
Eighty-five lesions of pure, noninvasive intraductal carcinoma were analyzed by histologic subtypes. The comedo subtype, defined by a solid growth pattern, high nuclear grade, and central necrosis, accounted for only seven lesions (8.2%). Solid, micropapillary, or cribriform patterns with central necrosis comprised 16 cases (18.8%), micropapillary 19 (22.4%), and cribriform 22 (25.9%). The comedo subtype showed several features different from the other subtypes. They occurred in younger patients and had higher numbers of duct profiles with carcinoma and larger tumor diameters. The intensities of lobular cancerization and periductal stromal chronic inflammation were also marked in the comedo lesions. Two of three comedo lesions examined by flow cytometry showed aneuploidy. Three of five tumors with nipple involvement contained at least some comedo-type duct profiles. These findings indicate greater potential aggressiveness of the comedo subtype. In contrast, the micropapillary and cribriform subtypes had fewer involved duct profiles, lower nuclear grade, and less mitotic activity. Microcalcification identified histologically, multifocality, and multicentricity were present in 54.1, 74.1, and 13.8%, respectively, of all lesions examined, and there were no differences between subtypes. Thus, the operative treatment of the comedo subtype (based on spread of disease within the breast) may not need to be more extensive than for other types of intraductal carcinoma. Central necrosis may prove to be of considerably less importance than nuclear grade in future evaluations of intraductal carcinoma.
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