Chapter: Lymphatic malformations
Article: 4 of 14
Update: Mar 15, 2021
Author(s): Meyer, Lutz
The majority of cystic lymphatic malformations (hereafter “LM”) are visible at birth as a swelling or circumscribed mass, e.g., of the face, an extremity or a buttock. Large lymphatic malformations are being detected or suspected with growing frequency during prenatal ultrasound screening. This leads increasingly to prenatal counseling of pregnant women in specialized vascular anomaly centers and even to prenatal or perinatal treatment attempts, which are still at the experimental stage (punctures, sclerotherapy and systemic drug treatments, e.g., with sirolimus prenatally, the EXIT strategy perinatally).
Some lymphatic malformations are not detectable at birth. Very often against the background of general viral infections, mostly of the upper respiratory tract, the cysts of the lymphatic malformation created in the embryo will fill up and become noticeable as swelling, e.g., of the neck. In isolated cases, this does not happen until adolescence or adulthood.
Retroperitoneal lymphatic malformations can go unnoticed for years. Often, again in the context of a viral infection, smaller cysts swell to become larger ones and cause symptoms (swelling of the abdomen, intra-abdominal pain). Such LMs have been discovered during surgery when appendicitis or hydrocele is suspected. Intra-abdominal lymphatic malformations usually affect the mesentery of the intestine and cause palpable resistance in the abdomen or intestinal transit disturbances.
Intrathoracic LMs are usually revealed during imaging workup of other externally visible portions of an LM. The upper mediastinum is most commonly involved, with cysts of varying sizes surrounding the intrathoracic trachea and great vessels. The middle mediastinum is less commonly affected, extending to the diaphragm or, even further, to the retroperitoneum. Symptoms rarely occur when the middle mediastinum is involved. Symptoms of restrictive lung capacity may occur if a retropleural LM fills more than 50% of one half of the chest with subsequent hypoplasia of the displaced half of the lung.
Intra-orbital lymphatic malformations often cause exophthalmos as well as increased growth in size of the orbit due to pressure on the bony orbit, which additionally results in a shift of the ocular axis, usually caudally.
Vesicles often appear on the conjunctiva as well as infiltration of the eyelids and the inner corner of the eye.
Cutaneous lymphatic malformations often do not become apparent until several years postnatally. Multiple clusters of pinhead-sized vesicles on an area of the skin or on the mucosa of the oral cavity and tongue lead to the diagnosis. In some cases, they may also grow exophytically from the skin.