Low Grade Adenosquamous Carcinoma of the Breast
Differential Diagnosis
- Metaplastic carcinoma NOS
- Adenosquamous carcinoma may be considered a variant of metaplastic carcinoma
- It should be diagnosed separately because of its distinct histologic appearance and its low grade behavior
- Metaplastic carcinoma includes pure squamous carcinoma and usual infiltrating carcinoma with squamous metaplasia plus those with mesenchymal metaplasia
- Adenosquamous carcinoma may be considered a variant of metaplastic carcinoma
| Tubular Carcinoma | Low Grade Adenosquamous Carcinoma |
|---|---|
| Uniform, gaping tubules | Irregular, frequently compressed lumens |
| Tubules frequently have pointed ends | Tubules frequently have long comma-shaped tails |
| No squamous differentiation | At least focal squamous differentiation |
| No myoepithelial component | Myoepithelial cells prominently present around tubules |
.
- Some consider these to be the same entity in different locations
- Histologic appearance is identical
- Small numbers of cases and differences due to superficiality could account for the difference in behavior reported
| Infiltrating Syringomatous Adenoma of the Nipple | Low Grade Adenosquamous Carcinoma |
|---|---|
| Involves dermis and subcutis | Parenchymal lesion |
| No metastases reported | Infrequent metastases reported |
| Low Grade Adenosquamous Carcinoma | Adenomyoepithelioma |
|---|---|
| Squamous differentiation frequent | Squamous differentiation not described |
| Infiltrative pattern | Circumscribed, not infiltrative |
