an unusual adnexal tumor with differentiation towards hair follicle, with concomitant presence of trichofolliculoma, trichoepithelioma and pilomatricoma in one lesion: a case report

a case of an interesting previously unreported mixed adnexal tumor of the scalp of a 38 year old man is presented, which was composed of randomly dispersed areas of trichofolliculoma, trichoepithelioma, and pilomatricoma concomitantly. while these lesions are classified under adnexal tumors with differentiation towards hair follicle structures, controversy is present concerning the exact origin and the pathway of their differentiation. so the concomitant presence of them in one lesion may be strong evidence for a common origin or a common direction of differentiation.