Intraoral proliferative myositis: case report and literature review

Proliferative myositis is a rare, benign, reactive intramuscular lesion of fibroblastic/myofibroblastic origin; an identical lesion in a subcutaneous or fascial location is referred to as proliferative fasciitis. The rapid growth rate and unusual histopathologic features have frequently been mistaken for a malignant process and have promoted unnecessary invasive procedures. Here we present only the third oral case of proliferative myositis, arising from the tongue of a 65-year-old man.

Histologically, the resected lesion was composed of numerous fibroblastic or myofibroblastic spindle cells and variable numbers of large ganglion-like cells infiltrating between and around muscle fascicles, resembling a "checkerboard" configuration. A demographic profile of proliferative myositis of the head and neck is also provided, compiled from 19 patients culled from an English-language literature review and this report.

Incisional biopsy or fine-needle aspiration biopsy of proliferative myositis of the head and neck should lead to spontaneous resolution and is, therefore, sufficient to render the diagnosis and to provide conservative treatment. Recurrence is extremely rare.