Pure Mucinous Carcinoma of the Breast
Supplemental Studies
Immunohistology
- Demonstration of myoepithelial cells can confirm the in situ or benign nature of a process while their absence supports invasion
- We prefer to use both p63 and calponin on problematic cases
- A variety of markers have been used for myoepithelial cells:
| Marker |
Sensitivity |
Specificity |
| Calponin |
Excellent |
Very good |
| p63 |
Excellent |
Excellent |
| Smooth muscle myosin heavy chain |
Good |
Excellent |
| CD10 (CALLA) |
Good |
Good |
| High molecular weight cytokeratin |
Very good |
Poor |
| Maspin |
Good |
Poor |
| S100 |
Good |
Very poor |
| Actin |
Good |
Very poor |
- Estrogen receptor (ER) and progesterone receptor (PR) are important markers for directing therapy and determining prognosis
- Current consensus is that any level of positivity should be reported as positive
- Her2neu status can be determined by either immunohistology or by FISH
- The other technique can be used for borderline cases
