Lymphangiomas are benign hamartomatous tumors of the lymphatic channels. They are thought to be developmental malformations arising from sequestration of lymphatic tissue that do not communicate with the rest of the lymphatic channels. They have a marked predilection for the head and neck region, which accounts for about 75% of all cases. About 50% of the lesions are noted at birth and around 90% develop by 2 years of age. They are known to be associated with Turner's syndrome, Noonan's syndrome, Trisomies, Cardiac anomalies, Fetal hydrops, Fetal alcohol syndrome, and Familial pterygium colli. Cystic hygroma in a child can grow suddenly due to infection or hemorrhage but can also shrink spontaneously.
Lymphangioma can be classified into four categories:
1) lymphangioma simplex (capillary lymphangioma, lymphangioma circumscriptum), composed of small, thin-walled lymphatics.
2) cavernous lymphangioma, comprised of dilated lymphatic vessels with surrounding adventitia.
3) cystic lymphangioma (cystic hygroma), consisting of huge, macroscopic lymphatic spaces with surrounding fibrovascular tissues and smooth muscle.
4) benign lymphangioendothelioma (acquired progressive lymphangioma), lymphatic channels appear to be dissecting through dense collagenic bundles.
The sub types are probably variants of the same pathologic process and depend on the size of the vessel and nature of the surrounding tissues. Cystic lymphangioma (cystic hygroma) mostly occurs in the neck and axilla as the loose adjacent connective tissues facilitate more expansion of the vessels.
Ravi Meher, Ashu Garg, Anoop Raj, Ishwar Singh: Lymphangioma Of Tongue. The Internet Journal of Otorhinolaryngology. 2005. Volume 3 Number 2.