Anatomic Pathology: Breast Pathology

• Figure 1 of the image depicts a cystic hypersecretory intraductal carcinoma. It is an unusual variant of intraductal cancer showing a micropapillary architecture.

• The cystic hypersecretory intraductal carcinoma is identified in a background of cystic hypersecretory hyperplasia (Figure 2). Cystic hypersecretory hyperplasia is characterized by multiple cysts with colloidlike eosinophilic secretions. Retraction of the colloidlike material is frequently seen. Varying degrees of epithelial hyperplasia and atypia may be seen.

• Cystic hypersecretory intraductal carcinoma may be confused with atypical ductal hyperplasia or may be overlooked.

• Intraductal cystic hypersecretory carcinoma typically demonstrates a crowded micropapillary pattern of growth, which may interconnect to form Roman bridging architecture.

• The invasive carcinoma associated with this form of intraductal cancer has primarily been poorly differentiated ductal carcinoma.

• The concomitant presence of pregnancylike (pseudolactational) hyperplasia and atypia and cystic hypersecretory hyperplasia and cystic hypersecretory intraductal carcinoma as well as low-grade invasive ductal carcinoma has been reported.