Pilar sheath acanthoma is an uncommon small benign tumour originating from the hair follicle. It is usually a small, solitary papule up to 5 mm in diameter with a tiny 1-2 mm central depression or opening. No hair grows from it and if squeezed, dead skin tissue is expressed.
They occur most often on the face and head of middle-aged men and women. In many cases lesions appear on the skin of the upper lip. Apart from their physical appearance they show no other signs or symptoms. They have not been associated with any other medical syndromes or skin tumours.
A small biopsy (when a tiny piece of skin is removed under local anaesthetic) is the only definitive diagnosis for pilar sheath acanthoma. The histology of pilar sheath acanthoma will differentiate it from other benign follicular tumours that have similar clinical presentations, these include dilated pore of Winer and trichofolliculoma.
Pilar sheath acanthoma is a benign follicular tumour that requires no treatment. Occasionally they may be excised for cosmetic reasons or if they occur in functionally sensitive areas. Treatment options include curettage and electrodesiccation or surgical excision.
