Atypical ductal hyperplasia
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);[3] however, it has a limited extent, i.e. is present in a very small amount (< 2 mm).
The rate at which breast cancer (ductal carcinoma in situ or invasive mammary carcinoma (all breast cancer except DCIS and LCIS)) is found at the time of a surgical (excisional) biopsy, following the diagnosis of ADH on a core (needle) biopsy varies considerably from hospital-to-hospital (range 4-54%).
[7] In two large studies, the conversion of an ADH on core biopsy to breast cancer on surgical excision, known as "up-grading", is approximately 30%.
[7][8] The relative risk of breast cancer based on a median follow-up of 8 years, in a case control study of US registered nurses, is 3.7.
- A - One focus (< 2 mm) of two architecturally disarranged cross sections of tubuli showing a monotonous intraductal proliferation with secondary intraluminal architecture. Hematoxylin and Eosin stain.
- B - One area of an ADH with associated calcifications intraluminal. Hematoxylin and Eosin stain.
- C - Higher magnification of ADH shows low-grade nuclear atypia and monotonous cell proliferation along with secondary intraluminal architecture. Hematoxylin and Eosin stain.
- D - Strong and uniform expression of estrogen receptors (ER). ER immunohistochemistry.
- E - Lack of basal cytokeratins (CK5/6). CK5/6 immunohistochemistry.