Purpose or Case Report:
Clinical signs of the Neonatal Lymphatic Flow Disorder (NLFD) are a combination of the congenital chylothorax, chylous ascites and body edema. It can present as neonatal chylothorax (NC), neonatal chylous ascites, or congenital lymphatic dysplasia (CLD). The prenatal appearance of lymphangiectasia has been described as nutmeg lung. The purpose of this study is to describe prenatal and postnatal imaging features and outcomes of neonates with NLFD.

Methods & Materials: This is a retrospective case series of all neonates in our institution that had pre- and postnatal lymphatic imaging and NLFD. All patients (pts) had prenatal imaging (fetal MRI and US) and postnatal three-dimensional (3D) T2 SPACE and dynamic contrast MR lymphangiography (DCMRL). Conventional lymphangiography (CL) when performed was reviewed.
Results: 6 pts with NLFD were identified (3 with NC and 3 with CLD). One pt had congenital heart disease. Nutmeg lung was seen in all pts on fetal MRI and 4 pts on fetal US [Figure 1]. 5/6 pts had pleural effusions, 2/6 had ascites and 1/6 had body wall edema prenatally. Postnatal MRI with 3D T2 SPACE revealed soft tissue edema in the upper chest and neck (5/6 pts), mediastinal edema (5/6 pts), interstitial lung edema (6/6 pts), retroperitoneal edema (5/6 pts), and ascites (6/6 pts). DCMRL demonstrated lymphatic flow to the pleural space (5/6 pts) and to the abdominal cavity (1/6 pts) [Figure 2]. There was increased enhancement of the retroperitoneum (5/6 pts) and dermal backflow (2/6 pts). CL was performed in 4 pts, all of which had collateral lymphatic flow to the lung. Lymphatic intervention was performed in 3 pts. Lipiodol injection was performed for 2 pts with NC and 1 pts with CLD underwent thoracic duct embolization (TDE). Mean hospital duration in the first 4 months (mo) of life was 51 days (range 5-113) for NC and 105 days (range 75-120) for CLD. All 3 pts with CLD died after 4 mo of age due to respiratory distress including the pt that had TDE. The pleural effusions in the 2 pts with NC resolved post lipiodol injection and in the other NC pt it resolved with conservative therapy.
Conclusions: NLFD is a disorder that can be recognized on prenatal and postnatal imaging. In this small series, nutmeg lung was present in all pts with NLFD and may be easier to recognize with fetal MR than US. Dermal backflow on DCMRL suggests a poor prognosis. Both prenatal and postnatal imaging may guide treatment and interventions in NLFD.