Epidermoid cyst in the temporomandibular joint after a dermal graft.

A very rare case of epidermoid cyst of the left temporomandibular join (TMJ) after a dermal graft inserted as the interposing material in the surgical correction of TMJ ankylosis is presented. Two years after the surgery, a cystic lesion the size of a walnut was observed in the TMJ region. The cyst contained an odorless, straw-coloured mucoid fluid and a wall lined by stratified squamous epithelium containing orthokeratin. It contained no hair follicles or sweat glands.