Carcinoma arising from epithelial lining the terminal duct lobular unit.
Carcinoma in situ (non-invasive)- when malignant cells have not invaded the basement membrane.
Ratio of DCIS to LCIS is 3:1
- Ductal carcinoma in situ (DCIS) -
- more common. 3-4% of symptomatic, 25% of screen-detected cancers (microcalcifications in mammogram).
- Lobular carcinoma in situ (LCIS) -
- a marker of increased risk of future invasive cancer.