- Microinvasive carcinoma is diagnosed when one or more separate foci of invasion measure 1 mm or less in maximum dimension.
- Nodal mets 1-10%; long term survival between DCIS & Stage 1](← Foci of tumour cells %3C 0.1cm in diameter invading the stroma
- If becomes invasive – retains original morphology & grade
- Staged as T1mi
- Invariably encountered in the setting of ductal carcinoma in situ (DCIS)
- Invasion is present in 25% of pts with DCIS
- Likely should have SLNB although axilar usually negative
- Nodal mets 1-10%; long term survival between DCIS & Stage 1