This video is about the classical trichoepithelioma. These are benign skin adnexal tumours that show hair follicle differentiation. They are composed of basaloid cells, horn cysts may be present and foreign body giant cells and granulomas may be seen as a reaction to liberated keratin from ruptured horn cysts. Trichoepitheliomas may be solitary or less frequently multiple with an autosomal dominant inheritance. The main differential diagnosis is basal cell carcinoma.