The delimitation of tubular carcinoma of the breast

Five hundred consecutive breast carcinomas from the first screening round o f the Breast Cancer Detection Demonstration Project were studied quantitati vely and semiquantitatively for features relevant to the diagnosis of tubul ar carcinoma. Tubularity was defined as the proportion of tumor cells that were adjacent to an open lumen. Nuclear morphology and mitotic activity wer e graded 1 to 3, and the presence of apocrine snouts as absent, few, common , or prominent. In plots and statistical cluster analysis, tubular carcinom a appears as part of a continuous spectrum of morphologies and not as a dis tinct entity. In multivariate analysis, apocrine snouts had no significant association with either nodal status or deaths of breast cancer. Tumors wit h 70% or greater tubularity by our definition and mitosis and nuclear grade s 1 were not associated with either nodal metastases or deaths of breast ca ncer. The question is raised whether tubular carcinoma at the benign end of a spectrum shades into benign glandular proliferations, with particular re ference to microglandular adenosis. A uniform and precise definition of tub ularity is needed for the attainment of sufficient collective experience to delimit tubular carcinoma both from more aggressive carcinomas and from be nign proliferations. Copyright (C) 2000 by W.B. Saunders Company.