Cystic hygroma is a rare congenital malformation of the lymphatic system. The lesion is characterized by the formation of a cystic mass of variable size. Most lesions are present in infancy or early childhood and are found predominantly in the region of the head and neck. This report describes a case with an unusual location of the lesion: A 12-year-old boy with a cystic hygroma in the shoulder presented with shoulder pain and swelling. The diagnosis was made by magnetic resonance imaging and confirmed after histologic examination of the resected specimen. This uncommon localization and condition of cystic hygroma should be included in the differential diagnosis of shoulder pain in children.