Lymphangiomatosis is a condition where a lymphangioma is not present in a single localised mass, but in a widespread or multifocal manner. It is a rare type of tumor which results from an abnormal development of the lymphatic system.

It is thought to be the result of congenital errors of lymphatic development occurring prior to the 20th week of gestation. Lymphangiomatosis is a condition marked by the presence of cysts that result from an increase both in the size and number of thin-walled lymphatic channels that are abnormally interconnected and dilated. 75% of cases involve multiple organs. It typically presents by age 20 and, although it is technically benign, these deranged lymphatics tend to invade surrounding tissues and cause problems due to invasion and/or compression of adjacent structures. The condition is most common in the bones and lungs and shares some characteristics with Gorham’s disease. Up to 75% of patients with lymphangiomatosis have bone involvement, leading some to conclude that lymphangiomatosis and Gorham’s disease should be considered as a spectrum of disease rather than separate diseases. When it occurs in the lungs, lymphangiomatosis has serious consequences and is most aggressive in the youngest children. When the condition extends into the chest it commonly results in the accumulation of chyle in the linings of the heart and/or lungs.

Chyle is composed of lymph fluid and fats that are absorbed from the small intestine by specialized lymphatic vessels called lacteals during digestion. The accumulations are described based on location: chylothorax is chyle in the chest; chylopericardium is chyle trapped inside the sack surrounding the heart; chyloascites is chyle trapped in the linings of the abdomen and abdominal organs. The presence of chyle in these places accounts for many of the symptoms and complications associated with both lymphangiomatosis and Gorham’s disease. The incidence of lymphangiomatosis is unknown and it is often misdiagnosed. It is separate and distinct from lymphangiectasis, lymphangioleiomyomatosis (LAM), pulmonary capillary hemangiomatosis, Kaposi’s sarcoma, and kaposiform hemangioendothelioma. Its unusual nature makes lymphangiomatosis (and Gorham’s disease) a diagnostic and therapeutic challenge. A multidisciplinary approach is generally necessary for optimal diagnosis and symptom management. The term literally means lymphatic system (lymph) vessel (angi) tumor or cyst (oma) condition (tosis).