[A patient with unilateral atrophy of trigeminal nerve-innervated muscle associated with contralateral glossopharyngeal and vagal neuropathy].

A 23-year-old woman was admitted to our hospital because of the left cheek swelling. On neurological examination, marked muscle atrophy of the right masseter muscle was recognized on chewing. The jaw was not deviated when she opened her mouth. Corneal reflex and the sensation on the face were intact. Curtain phenomenon was observed on the right side. The hypesthesia in the left palatal mucosa was observed. Routine laboratory data including cerebrospinal fluid analysis were normal. EMG from the right masseter muscle was not elicited, but normal in the left masseter muscle. The CT scan showed atrophy and low density areas in the right masseter, temporalis, lateral and medial pterygoid muscles, and hypertrophy in left masseter muscle. The MRI on T1 and T2 images confirmed the above muscle involvement. The etiology of trigeminal motor neuropathy, glossopharyngeal and vagal neuropathy were unknown. Masseter muscle hypertrophy was thought to be work hypertrophy compensated for the contralateral muscular atrophy.