Numbness in the tip of the tongue and lower lip caused by thalamic hemorrhage.

Although patients with isolated oral syndrome or facial sensory loss following stroke of thalamic ventroposteromedial (VPM) nucleus have been reported, there have been no reports of numbness in the tip of the tongue and lower lip. Furthermore, symptoms in the tip of the tongue caused by stroke are typically characterized as gustatory sensory disturbances. A 62-year-old hypertensive man experienced an acute onset of severe numbness in the left tip of the tongue and ipsilateral lower lip. Neurological examination revealed no other abnormalities except for the aforementioned numbness. Head computed tomography showed a small hematoma in the medial part of the right thalamus, most likely within the VPM nucleus. The somatosensory impulse of the tongue is conveyed via the lingual nerve, and it reaches the contralateral medial VPM proper via the trigeminal spinal nucleus. Therefore, thalamic stroke mainly involving the medial VPM proper has the potential to elicit numbness in the tip of the tongue. A major portion of the VPM nucleus is vascularized by the inferolateral arteries. The inferolateral arteries vary greatly in the number and position of the arteries and their tributaries, and small-vessel disease in this territory can present with diverse symptoms because of this complexity. These findings indicate that central neurological involvement should not be overlooked in the case of sensory disturbance restricted to the tip of the tongue and lip.