Proliferative myositis of the mylohyoid muscle.

Proliferative myositis (PM) is a head and neck mass of rare etiology. In a review of the literature, 57 cases of PM were found. Of these, only 12 occurred in the head and neck region. Proliferative myositis is most rare in children, with only three reported cases, none of which involved the head and neck region. A case of a 9-year-old girl with PM of the mylohyoid muscle, presenting as a neck mass, is reported.