In situ carcinomas of the breast. Types, growth pattern, diagnosis, and treatment.

The paper presents a prospective study comprising 40 consecutive patients with in situ carcinomas of the breast and two with atypical ductal hyperplasia (ADH) who underwent operation during a 2-year period at a single hospital. Out of the 40 in situ carcinomas 13 were of the lobular type (LCIS) and 27 of the ductal type (DCIS). They made up about 9% of all newly diagnosed breast cancers. Histologically a distinction could be made between three different growth patterns: microfocal, tumour-forming, and a diffuse form. With the exception of one case, the 26 microfocal growths (2 ADH, 13 LCIS, 11 DCIS) were accidental findings in otherwise benign breast biopsies, whereas the tumour-forming and diffuse forms (16 DCIS) were diagnosed in the great majority clinically and/or by mammography. Of the tumour-forming and diffuse DCIS 25% were demonstrated solely by mammography. The surgical treatment in the 26 patients showing microfocal changes was exclusively biopsy in 23, while three had mastectomy, because of a papillary focus in two and patient preference in one. Of six patients with tumour-forming DCIS three had segmental resection and three mastectomy, the latter because of papillary foci, while all 10 with diffuse growth had mastectomy. On the basis of their experience of types and growth patterns, the authors set up a surgical strategy which might add new aspects to our knowledge about the biological nature of in situ lesions.