FIG 1. Patient 1.

A, Noncontrast axial CT image shows myositis of the left masseter muscle with diffuse swelling, but without significant surrounding inflammatory change or definite fluid collection. The parotid gland is normal.

B, Six months later, postcontrast axial CT image shows increased masseteric swelling and mandibular sclerosis with a discrete area of low attenuation (black arrow) with probable rim enhancement, suggesting the presence of an abscess.