Sclerosing adenosis most commonly occurs as multiple microscopic foci, although occasionally it presents as a palpable mass.
Sclerosing adenosis most commonly occurs as multiple microscopic foci, although occasionally it presents as a palpable mass. It is formed by a proliferation of both stromal and epithelial elements of the terminal duct-lobular unit.
The hallmark of sclerosing adenosis is a cellular proliferation visible at low-power magnification that is lobular and limited to a discrete area. It is often difficult to identify the normal double-layered epithelium, and solid proliferations of myoid or epithelial cells may occur.
Microcalcifications, visible on mammography, are common in sclerosing adenosis. Thus, the condition may mimic carcinoma. That adenosis may also occur as a palpable mass and has a pseudoinfiltrative appearance complicates the differential diagnosis. Biopsy is advisable for pleomorphic clustered microcalcifications or for adenosis presenting as a mass or architectural distortion.