Diagnosis and Treatment of Lymphatic Plastic Bronchitis in Adults Using Advanced Lymphatic Imaging and Percutaneous Embolization

Rationale: Plastic bronchitis is a condition characterized by expectoration of branching bronchial casts. Although the mechanism of cast formation in adults with plastic bronchitis remains poorly understood, abnormal pulmonary lymphatic flow resulting in molding of congealing lymphatic fluids in the airway has been documented as a cause of the disease in children with congenital heart disease. Objectives: To use advanced lymphatic imaging techniques, including dynamic contrast-enhanced magnetic resonance (MR) lymphangiography (DCMRL) and intranodal lymphangiography, to investigate the mechanism of cast formation in adult patients with plastic bronchitis, and to evaluate the therapeutic outcome of percutaneous lymphatic embolization for these patients. Methods: Seven adults (male/female = 3/4, mean age = 50 yr) who presented with expectoration of branching bronchial casts were evaluated. Lymphatic imaging included heavy T2-weighted MR imaging and DCMRL. All patients underwent bilateral intranodal lymphangiography and thoracic duct cannulation. In cases where abnormal pulmonary lymphatic flow was demonstrated, embolization of pulmonary lymphatics was performed. Measurements and Main Results: DCMRL demonstrated the presence of abnormal pulmonary lymphatic flow in six of seven patients, which was confirmed by intranodal lymphangiography and thoracic duct injection to represent lymphatic reflux or communication with of abnormal lymphatic channels with airways. After lymphatic embolization using a combination of endovascular glue and coils, five patients reported immediate and complete resolution of the symptoms and one patient reported partial, but significant, improvement. Transient abdominal discomfort postprocedure was treated with analgesics and resolved before discharge in all subjects. The mean length of follow up was 11 months (range, 4.3-16 mo). Conclusions: We demonstrated abnormal pulmonary lymphatic flow on DCMRL and intranodal lymphangiogram in six of seven adult patients referred with expectoration of branching casts. Based on these data, we postulate that many cases of idiopathic plastic bronchitis in adults have a lymphatic basis, and propose that the diagnosis be renamed lymphatic plastic bronchitis in those subjects to distinguish the disorder from the other forms. Percutaneous transabdominal catheterization and embolization of the pulmonary lymphatics is a safe and effective treatment for the acute manifestation of this disorder, but additional studies are needed to determine the long-term safety and durability of this approach.