Rosen's Breast Pathology, 4e

363

Ductal Carcinoma In Situ

FIG. 11.40.  DCIS in sclerosing adenosis with invasion. A: DCIS ( above ) in SA. B: Area of sclerosis involved by DCIS. C: Invasive cribriform carcinoma originating in SA.

were neither palpable nor grossly evident, and were gener- ally of smaller extent with variable histologic type (including cribriform, micropapillary, and papillary) and comprised cells with lower grade nuclei and exhibited no necrosis. Then, as now, a proportion of comedo and noncomedo types of DCIS comprised combinations of growth patterns and nuclear grade. Comedocarcinoma is “high” grade by definition. Poorly differentiated nuclei, usually accompanied by necrosis, are also infrequently encountered in papillary, micropapillary, and cribriform DCIS 149 (Figs. 11.19, 11.25, and 11.51). DCIS is in the intermediate-grade category when it has a cribri- form, solid, or papillary pattern with necrosis but lacks the nuclear anaplasia of comedocarcinoma, or if one of these growth patterns is composed of high-grade carcinoma cells in the absence of necrosis (Figs. 11.9, 11.11, 11.21, and 11.26). Any pattern of DCIS composed of uniform cells without atypia or necrosis is classified as low grade (Figs. 11.2, 11.4, 11.7, 11.15, 11.21, 11.43, and 11.52). A case is usually clas- sified on the basis of the highest grade present. 151 Rarely,

FIG. 11.41.  Invasive carcinoma arising in sclerosing ad- enosis. DCIS in SA is shown on the right in this section prepared with the immunostain for SMM-HC. Invasive car- cinoma in the stroma to the left of the SA is not encased in actin-positive myoepithelial cells.