Suspicious mass and calcifications, thought to represent ductal carcinoma in situ when biopsied. A lumpectomy was performed.
Case Discussion
Adenosis is a benign proliferation of normal breast glands. It may be accompanied by stromal sclerosis and form a mass-like lesion as in this case. The differential diagnosis includes microglandular adenosis (MGA) and invasive ductal carcinoma, tubular type (both lack myoepithelial cells, immunohistochemically MGA is S100 positive and ER negative, tubular carcinoma is ER positive).
Slodkowska, E. Breast, Adenosis (Myosin/Smooth Muscle Stain). Digital Laboratory Medicine Library, Dept of Laboratory Medicine & Pathobiology, University of Toronto. Published
. Accessed December 17, 2025. https://dev.dlml.cflabs.ca/image/breast-adenosis-myosinsmooth-muscle-stain-lmp97418
