Myoepithelioma of the Breast
Differential Diagnosis
| Myoepithelial Carcinoma |
Myoepithelioma |
| Cytologically malignant |
Cytologically bland |
| Frequent mitotic figures |
Mitotically inactive |
| Necrosis may be present |
No necrosis |
| Myofibroblastoma |
Myoepithelioma |
| Circumscribed |
May be stellate |
| Keratini negative |
Keratin positive |
| CD34 positive |
CD34 not reported but expected to be negative |
| Metaplastic Carcinoma |
Myoepithelioma |
| Contains malignant epithelial component |
No epithelial component |
| Mesenchymal component, if present is usually cytologically malignant |
Bland spindle cell population |
