Useful histological and immunohistochemical features for distinguishing between basal cell carcinoma and trichoepithelioma
| Feature | BCC | TE |
|---|---|---|
| BCC, basal cell carcinoma; CK, cytokeratin; TE, trichoepithelioma. | ||
| Histology | Increased mitoses | Mitoses not increased |
| Retraction spaces | Retraction spaces not present | |
| Usually no horn cysts | Horn cysts usually present | |
| Stromelysin 3 | Positive in stroma | Negative |
| CD10 | Positive in basaloid cells | Positive in stroma |
| CD34 | Negative | Positive in stroma |
| Bcl-2 | Diffusely positive in basaloid cells | Positive in peripheral cells only |
| Ki-67 | Increased (20–40%) | Normal (rare cells) |
| CK 15 | Negative | Focally positive |
| CK 20 | Negative | Focally positive |