Proliferative myositis in the head and neck

Benign fibrous lesions in the head and neck include lesions with a wide range of histologic features. Some of these conditions may be mistaken for malignant tumors, leading to unnecessary radical therapy. Proliferative myositis is one such lesion. A 49-year-old man had a one-week history of swelling over the left side of this mandible and upper neck. Most of the mass was removed and the diagnosis of proliferative myositis was confirmed by excisional biopsy. The patient was free of disease one year after surgery.