Intramasseteric schwannoma in a child.

Schwannoma arising in muscle is rare. We treated a very unusual case of schwannoma originating in the masseter muscle in a 12-year-old boy, who presented with a 1-year history of a painless left cheek mass. CT and MRI revealed that the mass existed in the masseter muscle. It was extirpated under general anesthesia without postoperative sequelae. The whitish mass was solid and encapsulated, and pathologic examination confirmed the diagnosis of schwannoma consisting of Antoni A and Antoni B areas. Definitive diagnosis of schwannoma before surgery is usually difficult; hence, histological examination during or after surgery is, in most cases, decisive. However, schwannoma should be considered in the preoperative differential diagnosis of intramuscular tumor, despite its rare occurrence, since postoperative neurological sequelae may occur.

Positional and positioning nystagmus in healthy subjects under videonystagmoscopy.

OBJECTIVE: The eye-focused video camera as sensitive to infrared light is very useful for detecting nystagmus with open eyes in the dark. The existence of physiological nystagmus has been reported. We investigated how frequently physiological positional and positioning nystagmus is seen in healthy individuals under infrared video goggles. MATERIALS AND METHODS: Eighty-nine healthy individuals were examined in this study. Positional and positioning nystagmus was examined with infrared video goggles. RESULTS: Positional nystagmus could be detected in 65 of the 89 subjects under infrared video goggles. The majority of nystagmus was horizontal nystagmus, and vertical nystagmus was also seen in four subjects. Nystagmus was most frequently recognized in right or left shoulder down position. Positioning nystagmus was detected in 40 subjects. CONCLUSIONS: Positional and positioning nystagmus frequently exist in healthy subjects. This finding means that the existence of physiological nystagmus must be considered when diagnosing dizzy patients using this equipment.