A Quantitative Study of Patterns of Basement Membrane in Ductal Carcinoma In Situ (DCIS) of the Breast

Abstract

Abstract: The pattern of basement membrane (BM) deposition was assessed in 20 cases of pure ductal carcinoma in situ (DCIS) and in 10 cases of DCIS with a focus of microinvasive carcinoma (DCISM) of the breast, using an indirect immunoperoxidase technique to detect type IV collagen. The presence and frequency of breaks in the BM was analyzed quantitatively. Normal breast tissue, benign breast lesions, and non-neoplastic mammary ducts adjacent to DCIS showed a continuous BM. In pure DCIS small areas of discontinuity in the BM were observed. The BM pattern of DCISM was similar to pure DCIS except at the point of microinvasion, where there was fragmentation of BM and wider areas of discontinuity with the presence of neoplastic cells extruding into the stroma. There was a significant correlation between the number of BM breaks in DCIS and histological type (p < 0.001) and nuclear grade (p < 0.001) with comedo type, high nuclear grade (grade 3) DCIS showing the largest numbers of discontinuities. Although there is a trend towards increased numbers of breaks in DCISM compared with non-invasive disease, this does not reach statistical significance (p > 0.05). We, therefore, suggest that the finding of a focus of microinvasion in DCIS is not an ominous prognostic indicator and the natural history of this entity is more similar to pure DCIS rather than to invasive breast cancer. Clinical follow-up was available for all the patients and the period ranged 21 to 55 months from the time of diagnosis. No patients have had a documented recurrence during this period. However, a longer term follow-up is needed to confirm this observation in this small series of patients who had undergone optimal treatment for the disease. BM staining, using type IV collagen antibodies may be of value to the diagnostic histopathologist in selected cases of DCIS to confirm a suspicious focus of invasion and to define accurately the morphologic nature of the lesion.