Apocrine Carcinoma of the Breast
Differential Diagnosis
| Apocrine Carcinoma |
Secretory Carcinoma |
| Large vesicular nuclei with prominent nucleoli |
Low grade nuclei with inconspicuous nucleoli |
| Cytoplasm granular, eosinophilic |
Cytoplasm granular or clear and vacuolated |
| PASd may show granular cytoplasmic staining |
PASd shows abundant cytoplasmic mucin |
| No predilection for young patients |
Most cases <30 years |
| Many show aggressive behavior |
Excellent prognosis |
| Histiocytoid Carcinoma |
Apocrine Carcinoma of the Breast |
| Amphophilic to weakly eosinophilic cytoplasm |
Intensely eosinophlic cytoplasm |
| Cytoplasm vacuolated, occasionally granular |
Cytoplasm granular |
| Indistince cytoplasmic borders |
Sharp cytoplasmic borders |
| Small nuclei and nucleoli |
Large vesicular nuclei with prominent nucleoli |
| Appears to have more aggressive behavior than usual carcinoma |
Appears to have better behavior than usual carcinoma in some series |
Some consider histiocytoid carcinoma to be a variant of breast carcinomas with apocrine features
| Lipid Rich Carcinoma |
Apocrine Carcinoma |
| Cytoplasm clear to multivacuolated |
Cytoplasm nearly uniformly granular |
| Cytoplasm at most focally eosinophilic |
Cytoplasm nearly uniformly eosinophilic |
| Scant PASd positivity in cells |
Frequently PASd positive |
| Fat stains positive |
Fat stains negative |
| GCDFP15 variable/weak |
GCDFP15 strong positive |
Indistinguishable on H&E stain; clinical significance of difference unknown
