Atypical ductal hyperplasia

Atypical ductal hyperplasia (ADH) is the term used for a benign lesion of the breast that indicates an increased risk of breast cancer. The name of the entity is descriptive of the lesion; ADH is characterized by cellular proliferation (hyperplasia) within one or two breast ducts and (histomorphologic) architectural abnormalities, i.e. the cells are arranged in an abnormal or atypical way. In the context of a core (needle) biopsy, ADH is considered an indication for a breast lumpectomy, also known as a surgical (excisional) biopsy, to exclude the presence of breast cancer. ADH, generally, is asymptomatic. It usually comes to medical attention on a screening mammogram, as a non-specific suspicious abnormality that requires a biopsy. ADH, cytologically, architecturally and on a molecular basis, is identical to a low-grade ductal carcinoma in situ (DCIS); however, it has a limited extent, i.e. is present in a very small amount (< 2 mm). Image:Atypical ductal hyperplasia - low mag.jpg | Low mag. Image:Atypical ductal hyperplasia - high mag.jpg | High mag. While the histopathologic features and molecular features of ADH are that of (low-grade) DCIS, its clinical behaviour, unlike low-grade DCIS, is substantially better; thus, the more aggressive treatment for DCIS is not justified. It is diagnosed based on tissue, e.g. a biopsy, showing ductal hyperplasia. There is no single definite cutoff that separates atypical ductal hyperplasia from ductal carcinoma in situ, but the following are important distinctive features of atypical ductal hyperplasia, with suggested cutoffs: Size less than 2 mm. Not involving more than one duct. The atypical epithelial proliferation is admixed with a second population of proliferative cells without atypia. The proliferation completely involves the terminal ductal lobular unit(s), to a limited extent. ADH, if found on a surgical (excisional) biopsy of a mammographic abnormality, does not require any further treatment, only mammographic follow-up.