Multidisciplinary Approach to the Management of Lymphatic Malformations of the Head and Neck.

Lymphatic malformations (LMs) occur in 2.8 to 5 per 100,000 live births. Most involve the head and neck and they are equally common in men and women. They are developmental anomalies of unknown cause, although recent evidence suggests that an upregulation of the mammalian target of rapamycin (mTOR) pathway may be a causal factor leading to the overproduction of abnormal lymph vessels. These vessels are likely dilated lymphatic sacs sequestered from the lymphatic and venous systems. This overproduction results in the accumulation of lymph in dilated cystic spaces, which in turn results in the clinical features of an LM.