benign proliferative disease

Three common pathologies and often mixed in an individual case:

 usual epithelial hyperplasia (UEH)
 apocrine metaplasia
 apocrine adenosis
 columnar cell change

They may all show a continuous spectrum of abnormalities from benign through atypical to in situ carcinoma.

 usual epithelial hyperplasia (UEH)

• intraduct benign epithelial proliferation
• epithelial and myoepithelial cells proliferate together
• Therefore mixed pattern seen on CK 5/6 or P63 immunostaining
• Streaming pattern usually seen
• Peripheral slit-like spaces within ducts
• Cells smaller, more crowded and overlapping than in atypical proliferations or CIS
• peripheral slit-like spaces
• streaming of ovoid shaped cells
• presence of cellular overlap
• heterogeneous pattern indicating two cell types
• possible area of columnar cell change without atypia
• The CK 5/6 stain shows abundant myoepithelial cells admixed with the proliferation

 apocrine metaplasia

• Often associated with cysts - less frequently with calcs
• May be seen focally within other lesions e.g. fibroadenomas
• Intraduct benign epithelial proliferation which may extent to acini
• Large cells with abundant eosinophilic cytoplasm, large nuclei with single prominent nucleolus
• May form luminal papillary tufts
• May be cytologically worrying but apocrine DCIS is uncommon.

 apocrine adenosis

 columnar cell change

• Also known as "Columnar Alteration with Prominent Snouts & Secretions (CAPSS)
• Often picked up at screening because of calcs
• Range of changes from simple through atypical to DCIS
• Tall coumnar cells with luminal-facing snouts
• May give a worrying FNA pattern because columnar cells tend to disperse and appear as single cells on smears
• Columnar cell hyperplasia with architectural atypia

Links

 http://www.breastpathology.info/Benign%20proliferative%20disease.html