Microglandular Adenosis of the Breast
Definition
- A haphazard proliferation of uniform, cytologically bland glands
Diagnostic Criteria
- Small, uniform open round glands
- Lined by uniform cuboidal to slightly flat cells
- Nuclei frequently flattened, parallel to circumference of gland
- Clear to eosinophilic cytoplasm
- Lumenal eosinophilic colloid-like secretion
- Occasional luminal calcification
- Cytologically bland
- Small indististinct nucleoli
- Mitotic figures uncommon
- Haphazard distribution
- Poorly circumscribed
- No lobular grouping
- Not stellate
- Frequently overruns normal elements
- No perineural or vascular invasion
- Background of fibrous or fatty tissue
- No spindle cell or desmoplastic component
- No myoepithelial layer
- Carcinoma, in situ and invasive, has been reported in association with microglandular adenosis
- Reported in up to 27%
- Apparently disproportionate numbers of metaplastic, adenoid cystic and basal-like carcinomas
- Transitional atypical microglandular adenosis has been proposed
- Increased irregularity and density of glands
- Increased cytologic atypia
- Hyperchromasia, prominent nucleoli, apoptosis
- Increased Ki67 and p53 staining (5-10% of cells)
- Carcinomas retain the immunophenotype of microglandular adenosis
Richard L Kempson MD
Robert V Rouse MD
Department of Pathology
Stanford University School of Medicine
Stanford CA 94305-5342
Original posting:: May 15, 2006
Updates: January 20, 2009