1.4 Central Conducting Lymphatic Anomaly
Central conducting lymphatic anomaly (CCLA) encompasses disorders that are caused by dysfunction of the thoracic duct and/or cisternae chylae with subsequent reflux and leakage of lymphatic fluid, most commonly into the lungs and/or abdomen [1]. Pleural and pericardial effusions, ascites and generalized edema are common and can result in organ dysfunction, protein loss and infections. Although medical history, physical exam and standard imaging may be suggestive of CCLA, definitive diagnosis requires lymphangiography demonstrating enlargement of lymphatic channels (lymphangiectasia), lymphatic fluid reflux and/or failure to empty into the thoracic duct or the subclavian vein at the thoracic duct outlet. Dynamic magnetic resonance lymphangiography may also be used for diagnosis and to help guide treatment but is not widely available [11, 12].
Treatment is largely supportive. Medical therapies have historically been limited to compression garments and replacement of albumin and immunoglobulins. Disease-modifying agents such sirolimus have been used but response is unclear, although a pathogenic EPHB4 (ephrin type-B receptor 4) variant was recently discovered, suggesting a potential role for mTOR or MAPK/MEK inhibitors [13]. Surgical procedures such as re-implantation of the thoracic duct or embolization of refluxing channels may also be a treatment consideration.
Table 1 provides a summary of the clinical features of these CLA.
MANAGEMENT PRINCIPLES FOR COMPLEX LYMPHATIC ANOMALIES