Infiltrating Ductal Carcinoma of the Breast (Carcinoma of No Special Type)
Differential Diagnosis
- Infiltrating lobular carcinoma
- Sclerosing adenosis
- Microglandular adenosis
- Radial scar
- Tubular carcinoma
- Carcinoma of unknown origin
| Infiltrating Ductal Carcinoma | Infiltrating Lobular Carcinoma |
|---|---|
| Infiltration in cords of varying thickness | Single file infltration |
| May form ductal structures | No duct formation |
| E-cadherin positive | E-cadherin negative |
| Infiltrating Ductal Carcinoma | Sclerosing Adenosis |
|---|---|
| Infiltrating | Circumscribed, nodular |
| Myoepithelial cells absent | Myoepithelial cells present |
| Infiltrating Ductal Carcinoma | Microglandular Adenosis |
|---|---|
| Infiltrating | Nodular or diffuse |
| Variable and irregular duct formation | Uniformly round ducts |
| Empty lumens | Eosinophilic secretion usually present in lumens |
| EMA positive | EMA negative |
| Basement membrane absent | Basement membrane variable |
| Infiltrating Ductal Carcinoma | Radial Scar |
|---|---|
| Cells may show various levels of atypia | Cytologically bland cells |
| No myoepithelial cells | Myoepithelial cells present |
| Frequent infiltration of fat by naked tubules | No bare infiltration of fat |
| May show various infiltrative patterns | Stellate configuration |
| Tubular Carcinoma | Grade I Infiltrating Ductal Carcinoma, NOS |
|---|---|
| Stellate infiltration | Irregular infiltration |
| 90% tubules | May have >10% ribbons or cords |
| Infrequent branching | Frequent budding and branching |
| Single layer of cells | May show stratification |
| Uniform chromatin | Slightly irregular chromatin |
| Nucleoli inconspicuous | Nucleoli may be prominent |
Breast vs. other origin in carcinoma of unknown primary
- See Supplemental Studies for useful immunologic markers
