Unilateral tongue atrophy due to an enlarged emissary vein in the hypoglossal canal.

A 16-year-old girl presented to our clinic with right-sided tongue atrophy and fasciculations of 1-year duration. Enlargement of the outer opening of the hypoglossal canal was reveal by conventional and computed tomography of the skull. Magnetic resonance imaging disclosed an enlarged venous system extending from the jugular vein to the internal jugular vein on the right, with low signal density suggestive of a flow void. A right-sided occipital craniotomy was performed. When the hypoglossal canal was opened, an enlarged emissary vein compressing the hypoglossal nerve was identified. This is the first reported case of unilateral tongue atrophy and an enlarged hypoglossal canal due to an enlarged emissary vein.