Cystic hygromas are cystic lesions that are usually found in the neck. They are caused by dilated, or enlarged, lymphatic tissue that becomes malformed, resulting in a type of benign tumor. Cystic hygromas develop at approximately 40 days of gestation because of a failure of the embryonic lymphatics to connect with the venous system. Cystic hygromas can be present at birth or can develop in early childhood. These cysts are filled with lymphatic fluid and lymph cells and may be inherited as through an autosomal recessive trait (National Organization for Rare Disorders [NORD], 2001). They are most frequently located in the posterior lower area of the neck, and they occur twice as often on the left side.
A cystic hygroma is a type of benign tumor known as a lymphangioma, typically appearing around the head and neck, armpits, or groin, and filled with clear fluid. These tumors are generally present at birth, growing to their largest size by the child’s second year, and then gradually diminishing. If the tumor is interfering with the airway, surgical removal might be necessary. However, the ultimate outcome is usually more satisfactory if surgery can be avoided.