The lesion is a benign-appearing, circumscribed proliferation of cytologically bland ductal and myoepithelial cells (2-layered epithelium). Often times, there will be a scar within the center of the lesion with proliferating tubules more towards the periphery.
Ductal cells can be compressed by intercellular stromal fibrosis, thus giving the lesion a pseudoinvasive look (upper area).
Ductal adenoma constitutes the third major type of adenoma in the breast, in addition to the nipple adenoma and tubular adenoma. Coined in the late 1980's, the term ductal adenoma is used to describe a set of benign, solid encapsulated lesions of the breast thought to communicate with the mid to proximal mammary duct system.
Many are thought to evolve through sclerosis of benign intraductal papillomas, although the precise pathogenesis is unclear.
May present as a single or multiple breast masses, often times mimicking a malignant process. Less often, it can present with nipple discharge.
Complete excision is curative.
- Its tendency to affect older age groups, contain microcalcification and the firmness and irregularity of many lesions can simulate malignancy
Rosen PP. Rosen's Breast Pathology. 3rd Ed. Philadelphia: Lippincott Williams & Wilkins.
Lammie GA et al. Ductal Adenoma of the Breast: A Review of Fifteen Cases. Human Pathology. (1989)20:9;903-8.