The value of androgen receptor, cytokeratin 20, and cytokeratin 7 expression in differentiating basal cell carcinoma from trichoepithelioma

Background Trichoepithelioma (TE) is a benign neoplasm that shares both clinical and histological features with basal cell carcinoma (BCC). It is important to distinguish these neoplasms because they require different therapeutic planning. Many studies have addressed the use of immunohistochemistry to improve the differential diagnosis of these tumors. Evaluation of androgen receptor (AR), cytokeratin 20 (CK20), and CK7 expression may aid in distinguishing the two tumors. Materials and methods Immunohistochemical expression of AR, CK20, and CK7 was studied in 30 cases of TE and BCC. Results AR was expressed in 11 of 15 cases of BCC (73.3%) whereas it was not expressed in any of the cases of TE 0/15 ( P <0.001). CK20-positive Merkel cells were identified in all cases of TE as compared with negative expression in all cases of BCC ( P <0.001). CK7 was expressed in six of 15 cases of BCC (40%) as compared with negative expression in all cases of TE. Conclusion AR and CK20 immunostaining can be very useful in differentiating TE from BCC, whereas CK7 expression plays a less important role.