Trichoepithelioma is a neoplasm of the adnexa of the skin. Its appearance is similar to basal cell carcinoma. One form has been mapped to chromosome 9p21.

Types

Trichoepitheliomas may be divided into the following types:

Pathology

Trichoepitheliomas consists of nests of basaloid cells, with palisading. They lack the myxoid stroma and artefactual clefting seen in basal cell carcinoma. Mitoses are uncommon when compared to basal cell carcinoma.

Diagnosis

Trichoepiteliomas often contain Merkel cells; an immunostain for CK20 can be used to demonstrate this.