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