Mandibular enlargement: an unusual complication of a cervical cystic hygroma.

A 13-year-old boy with a large cervical cystic hygroma, which extended into the floor of mouth, was referred for treatment of painful teeth and tongue. Clinically there was a large submandibular swelling, enlargement of the mandible and a Class III malocclusion. Intra-orally the tongue was enlarged and vesiculated. Gross caries was present in both mandibular permanent first molar teeth. Treatment comprised oral hygiene instruction, dietary advice, chlorohexidene mouth rinse, and removal of the carious teeth. At a later data, removal of the lesion and correction of the mandibular enlargement will be undertaken.