Section: Breast Curriculum: Curriculum, page 9
Definition
- Intraductal proliferation of epithelial cells with fibrovascular cores and underlying myoepithelial cells
Incidence
- Most common aetiology of bloody discharge (50-57%)
- Most common in 30-40yo
- Risk of cancer sig ↑ > 40yrs
Aetiology
- Intraductal papilloma might originate from bipotent progenitor cells that differentiate as luminal and myoepithelial cells
Clinical
- Usually single duct, usually solitary, benign epithelial lesion “true polyps”
- Clear / serosanginous or (in 50%) blood-stained discharge
Pathology
- Benign intraductal proliferation of epithelial cells with fibrovascular cores and underlying myoepithelial cells
- Distinction with malignant papillary lesions may be difficult on biopsy and immunohistochemistry may be necessary
- Epithelial component can have changes ranging from
- Metaplasia, hyperplasia, atypical hyperplasia, in-situ carcinoma
Classification
- Solitary (90%)
- Papilloma without atypia: ~X2 if single; ~X3 if multiple
- Papilloma with atypia: ~X5 if single; ~X7 if multiple
- Multiple papillomas (Diffuse papillomatosis) (10%)
-
5 discrete lesions within localised segment of breast tissue
- Peripheral, can occupy multiple ducts, can be bilateral, usually younger pts
- May not have discharge but can present as mass
- ↑ risk of malignant change (similar to ADH/LCIS risk thus requires surveillance)
- Only malignant risk if contain areas of atypical hyperplasia
- Can progress to intraductal / intracystic papillary
-
Management
- Can rarely be malignant therefore are usually removed
- Papilloma without atypia - unclear, unlikely to be upgraded pathologically however given unknowns they are still typically excised in practice
- Previously though to be 5-20% risk of upgrade although likely much lower
- In a prospective trial by the Translational Breast Cancer Research Consortium (TBCRC) of 116 intraductal papillomas without atypia on core biopsy, excluding discordant findings, the upstage rate on local review was only 1.7 percent
- Previously though to be 5-20% risk of upgrade although likely much lower
- Papilloma with atypia - should be excised as upgraded pathologically 65% of the time
- Multiple papillomas/ diffuse papillomatosis - defined as a minimum of five papillomas within a localized segment of breast tissue and can be definitively managed with excision