Mammographic-Pathologic Correlation of Ductal Carcinoma In Situ of the Breast Using Two- and Three-Dimensional Large Histologic Sections

Specially adapted histology techniques (two- and three-dimensional large sections) and systematic radiologic-pathologic correlation of the findings facilitate the understanding of ductal carcinoma in situ (DCIS), a heterogeneous and progressive group of diseases. DCIS cases can be classified as special and non-special types both mammographically and histologically. The mammographic special forms are the non-calcified DCIS cases (dominant mass, galactography findings and architectural distortion). The mammographic special forms are the cases containing microcalcifications. In this review, the histologic distinction of special versus non-special forms of DCIS will be used. According to this, the special type of DCIS includes intracystic and intraductal papillary carcinomas, tumor forming DCIS, Paget's disease and other lesions while the non-special types of DCIS involves the lobules and the ducts of the breast. The special type DCIS cases are unifocal in 65%. In the majority (60%) of cases, DCIS of non-special type involves the lobules and disturbs the normal process of lobularization leading to development of well circumscribed, unifocal, or multifocal lesions, most often of low or intermediate histological grade. These lesions calcify in 80% of cases and manifest as clusters of powdery or crushed stone-like microcalcifications on the mammogram. Lesions involving the larger ducts develop a diffuse network of tubes, which is difficult to delineate or measure. The radiological hallmark of these cases is the presence of casting-type microcalcifications. In a considerable number of diffuse cases (almost exclusively high-grade) neoductgenesis can be observed as a sign of disturbed arborisation of the ductal system, which is regularly associated with signs of altered epithelial-stromal interaction (periductal fibrosis and lymphocytic infiltration as well as remodeling of the periductal stroma). The majority of cases in DCIS non-special type are multifocal or diffuse, and more than half of them are extensive (involving a larger area than 2 cm in diameter). Extensive DCIS cases with signs of neoductgenesis recur significantly more often than the rest. Micropapillary DCIS, especially if high-grade, is an extensive disease, which frequently recurs. The individual lesions in DCIS seem to be confined to a single sick lobe within the breast. An imaging method able to demonstrate the diseased lobe would be needed to remove DCIS in its entirety and prevent recurrences.