Magnetic resonance imaging in the diagnosis of asymmetrical bilateral masseteric hypertrophy.

Asymmetrical bilateral masseteric hypertrophy or unilateral masseteric hypertrophy may present a diagnostic dilemma. While the history and clinical examination are important in differentiating this benign condition from parotid and dental pathology, they cannot necessarily exclude rarer malignant lesions of or within the muscle itself. We present a case where MRI provided clear and elegant confirmation of our provisional clinical diagnosis by illustrating both the soft tissue features and the logical corresponding bony features of this condition, thus obviating the need for further invasive investigations.