Oncocytic Carcinoma of the Breast
Supplemental Studies
Immunohistology
- Anti-mitochondrial antibody positive
- GCDFP15 negative
- Chromogranin and synaptophysin negative
- Keratin positive 3/3 cases
- EMA positive 2/3 cases
- Smooth muscle actin negative
- Peripheral myoepithelial cells positive in in situ cases
- Demonstration of myoepithelial cells can confirm the in situ 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 - E-cadherin appears to be a sensitive marker of ductal differentiation vs lobular differentiation; its utility in borderline lesions is currently uncertain
- CK7 and CK20 have not been tested on a series of oncocytic carcinomas, thus their utility is unknown
Prognostic/Therapeutic Markers
- ER and PR positive in 2/3 reported cases of oncocytic carcinoma
- 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 case
Genetic analysis
-
Her2neu status can be determined by either immunohistology or by FISH
- The other technique can be used for borderline cases
Ultrastructure
- Mitochondria occupying at least 60% of cytoplasm
- Diffusely distributed throughout cytoplasm