A CASE OF PLASTIC BRONCHITIS POST EBUS-TBNA

Abstract

TOPIC: Lung Pathology TYPE: Medical Student/Resident Case Reports INTRODUCTION: Plastic bronchitis (PB) is a disorder in which intrapulmonary lymphatic overload or leakage causes retrograde thoracic lymphatic flow into lungs, forming mucofibrinous bronchial casts that can result in significant airway obstruction. PB is associated with congenital heart disease in children; in adults, etiology is less clear. Presentation is expectoration of thick, rubbery secretions with histopathology revealing cross-linked branching of mucin-containing, lymphocyte-predominant casts. However, without high clinical suspicion, this can be confused with mucous plugging or pneumonia. Here we present a case of plastic bronchitis in a patient after EBUS-TBNA for diagnosing and staging a lung nodule. CASE PRESENTATION: A 75-year-old woman with history of COPD and remote breast cancer with right mastectomy and radiation underwent EBUS with FNA of a right middle lobe lung mass found incidentally on a pre-operative chest x-ray. She was diagnosed with Stage III squamous cell carcinoma of the lung after EBUS-TBNA was done on stations 4R,7 and 11Rs. Shortly after EBUS she developed cough that progressed to acute dyspnea, wheezing and thick rubbery sputum production that did not improve with course of antibiotics and prednisone. Chest CT showed atelectasis of right upper and middle lobe with ground-glass opacification and interlobular septal thickening in right lower lobe. Bronchoscopy revealed an obstructive cast in the bronchus intermedius, extending into right middle and lower lobes, that was removed with Cryoprobe. Histopathology showed mucofibrinous material with lymphocytes & foamy macrophages consistent with Type II plastic bronchitis cast. She underwent IR lymphangiogram which showed proliferation of right mediastinal & intrapulmonary lymphatic channels with lobar/interlobar lymphadenopathy. She was treated with percutaneous embolization of thoracic duct and right mainstem peribronchial lymphatic channels, complicated by post-procedure pancreatitis. Symptoms slowly improved with aggressive chest physiotherapy and bronchodilators. No obstructive casts were seen on repeat bronchoscopy. One month later she was able to be discharged to begin chemo radiation. DISCUSSION: PB is likely more common than reported and most literature has focused on pediatric cases. PB can cause life-threatening events in 40 percent of cases, particularly if mis-diagnosed, and causative etiologies in adults are not fully understood. This patient's remote history of mastectomy with lymph node dissection and active malignancy may have put her at risk but the timing of symptoms raise concern that the EBUS itself may have been the trigger for development of PB. CONCLUSIONS: Our case illustrates that PB should be considered as a complication that can arise post EBUS in patients with impaired lymphatic drainage and previous radiation treatment. To the best of our knowledge this is the first reported case of PB post EBUS-TBNA. REFERENCE #1: Rubin B. Plastic Bronchitis. Clinics in Chest Medicine 2016; 37(3):405. REFERENCE #2: Coen M, Daniel L, Serratrice J. An adult case of plastic bronchitis: a rare and multifactorial disease. J Thorac Dis. 2018;10(1):E16-E19. REFERENCE #3: Madsen P, Shah SA, Rubin BK. Plastic bronchitis: new insights and a classification scheme. Paediatr Respir Rev 2005;6:292-300. DISCLOSURES: No relevant relationships by Edward Adams, source=Web Response No relevant relationships by Abduljabbar Dheyab, source=Web Response No relevant relationships by Shaun Toomey, source=Web Response