Myoepithelioma of the Breast
Definition
- Bland spindle cell lesion of the breast with a myoepithelial cell phenotype
Diagnostic Criteria
- Monomorphic cytologically bland spindle cells
- Elongate nuclei
- No pleomorphism
- No mitotic figures
- Clear to eosinophilic cytoplasm
- Interlacing groups of cells, may be stellate or solid masses
- May infiltrate fat
- May surround normal ducts
- Myoepithelial phenotype
