Unilateral hypoglossal nerve palsy due to neurovascular conflict in a child.

A neurovascular conflict (NC) consists of a pathological contact between a vessel, generally an artery, and the root entry zone of a cranial nerve close to the brainstem. Even if NC of the V, VII and IX cranial nerve have been rarely described, to the best of our knowledge there is no report about the XII cranial nerve NC in the paediatric age. A three-year-old girl presented with right-sided tongue atrophy and fasciculation, of one-year-duration, consistent with a peripheral lesion of the right XII cranial nerve. Brain MRI and MRA documented a marked tortuosity of the vertebrobasilar arteries compressing the brainstem at the emergency of the XII cranial nerve, while the CT disclosed a concomitant osseous malformation of the cranio-cervical junction. The differential diagnosis of a peripheral unilateral cranial nerve palsy should include, even if rare in children, a neurovascular conflict. In this case a complete neuroimaging study is indicated.