Ductal Carcinoma in Situ of the Breast
Minimal Stromal Invasion
Definition: Extension of cancer cells beyond the basment membrane into the adjacent tissue with no focus more than 0.1 cm in greatest dimension (AJCC T1mic)
Diagnostic Criteria
- Multiple foci are not added together for evaluation of the size criterion
- Calponin and p63 stains can be useful
- Focus should be outside the lobular unit or immediate periductal area
- If cells are present in these areas, designate as "scattered cells in perilobular or periductal area"
- Note in report that they do not meet the criteria for minimal stromal invasion
- Note that their clinical significance is unknown
- If cells are present in these areas, designate as "scattered cells in perilobular or periductal area"
- Significance
- Less than 5% chance of metastases
- Nearly 100% survival
- We avoid the term "microinvasion" because of its varying definitions
