Imaging of central lymphatic abnormalities in Noonan syndrome

Background: Children with Noonan syndrome are known to have increased risk for lymphatic disorders, the extent and nature of which are poorly understood. Objective: Our objective was to describe the imaging findings of the central lymphatic abnormalities in children with Noonan syndrome who underwent central lymphatic imaging. Materials and methods: We conducted a single-center retrospective review of all children with a confirmed history of Noonan syndrome who presented for lymphatic imaging over a 5-year period. Imaging evaluation was performed on unenhanced T2-weighted (T2-W) imaging, dynamic-contrast MR lymphangiography or conventional lymphangiography. Two readers evaluated the imaging in consensus for the distribution of fluid on T2-W imaging and for lymphatic flow of intranodal contrast agent and thoracic duct abnormalities on dynamic-contrast MR lymphangiography and conventional lymphangiography. We performed a chart review for clinical history and outcomes. Results: We identified a total of 10 children, all but one of whom had congenital heart disease. Presenting symptoms included chylothorax (n=9) and ascites (n=1). Nine had T2-W imaging, seven had dynamic-contrast MR lymphangiography, and seven had conventional lymphangiography. All with T2-W imaging had pleural effusions. On both dynamic-contrast MR lymphangiography and conventional lymphangiography, perfusion to the lung was seen (n=6), with intercostal flow also seen on dynamic-contrast MR lymphangiography (n=6). The thoracic duct was not present in three children and the central thoracic duct was not present in three. A double thoracic duct was seen in two children. Conclusion: Children with Noonan syndrome and clinical evidence of lymphatic dysfunction have central lymphatic abnormalities characterized by retrograde intercostal flow, pulmonary lymphatic perfusion, and thoracic duct abnormalities.