Breast adenosis is a proliferative condition characterized by histological hyperplasia that primarily involves the glandular component of the breast [1, 2]. It commonly presents with an enlargement of the affected breast lobule and terminal ductal lobular unit, as well as with an increased numbers of ductules and acini within the lobule. Different types of breast adenosis have been described such as sclerosing, microglandular, blunt duct, apocrine and adenomyoepithelial adenosis [1-17]. Sclerosing adenosis of the breast is the most common type of adenosis and can coexist with proliferative lesions as well as malignancies [3, 4, 7, 14]. Apocrine adenosis is used to describe sclerosing adenosis with apocrine changes [6, 9, 11, 12, 15]. Blunt duct adenosis is usually used to denote a lobular configuration of distended terminal ducts that have a columnar epithelium lining the central extracellular lumen. Calcium phosphate microcalcifications are often found clustered in these distended ducts and can mimic malignancy [1]. Although considered benign, adenomyoepithelial adenosis can also show local recurrence and malignant degeneration, therefore recurrence and even metastasis are important issues in the follow-up [16]. Microglandular adenosis is associated with glandular proliferation, being characterized by small glands lined by one layer of cuboidal epithelial cells encircled by basal lamina without any evidence of interposed myoepithelial elements [17]. Microglandular adenosis has also been reported to be associated with invasive carcinoma in up to 20-30% of cases and has been proposed as a non-obligate precursor to basal-like breast cancers [1, 5].