After extensive consultation with the patient and his family, the boy was taken to the operating room for surgical excision of the lesion (figure 2, A). Intraoperatively, the mass was found to contain numerous cystic spaces filled with blood and serosanguineous fluid (figure 2, B). The mass had enveloped cranial nerve XI, which was spared in its entirety. The excised mass measured 7 cm at its widest dimension (figure 2, C). The patient’s postoperative course was uneventful, and he experienced no surgical morbidity. Pathologic examination of the mass was consistent with a lymphatic malformation, also commonly referred to as a lymphangioma.

Lymphatic malformations are seen in 6,000 to 16,000 live births annually; 75 to 90% of these occur in the neck, particularly toward the left posterior cervical region. 1, 2 Traumatic injury and upper respiratory infection are common causes of a rapid expansion of an existing lymphatic malformation. 3 Surgical excision and intralesional sclerosing agents are the mainstays of treatment.