Focal myositis of the floor of mouth: report of two cases and review of the literature.

[focal myositis]

Focal myositis is an uncommon inflammatory myopathy of unknown cause affecting skeletal muscle . It may be mistaken on clinical evaluation for a malignant neoplasm . We describe two cases , both involving the mylohyoid muscle of the floor of the mouth . In each case excisional biopsy of a firm indurated mass revealed a focal lymphocytic and histiocytic infiltrate associated with degenerating and regenerating skeletal muscle fibers . No clinical or biochemical evidence of generalized muscle disease was seen at presentation or at 1 -year and 7 -year follow-up examination . The literature on focal myositis involving the head and neck region is reviewed .