The basement membrane and lobular carcinoma in situ of the breast.

The basement membrane (BM) was examined by light microscopy in cases of lobular carcinoma in situ of the breast (LCIS), employing the following stains: haematoxylin-eosin, van Gieson-Hansen, PAS, colloidal-iron-PAS, and reticulin. The BM was non-intact in 12 out of 26 investigated cases of LCIS when reticulin staining was applied, but appeared non-intact in about 70 per cents with the other staining methods. On the other side control areas of the BM were intact in 23 out of 26 cases with reticulin stain, but in only about half of the cases with other stains. It is concluded that reticulin staining is the most suitable in evaluating the BM in LCIS, and that more or less pronounced defects of the BM in LCIS cannot be considered evidence of imminent invasion. Although the overall occurrence of invasive breast carcinoma was significantly increased in 9 cases with epithelial cell protrusion through the BM, this feature should be investigated further before it is allowed to affect therapeutic decisions.