Esophageal duplication cyst diagnosed with ebus

SESSION TITLE: Fellows Disorders of the Mediastinum Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: October 18-21, 2020 INTRODUCTION: Esophageal duplication cysts are a rare congenital foregut anomaly often presenting in childhood as a mediastinal mass without communication with the esophagus. In adults, presentation varies based on location and compression of adjacent structures. This case is an incidentally found subcarinal mediastinal mass compressing the right mainstem bronchus highly suspicious for an esophageal duplication cyst diagnosed via endobronchial ultrasound. CASE PRESENTATION: A 61-year-old female active smoker referred for abnormal computed tomography (CT) of the chest with a 3-month history of fatigue, cough and a retroperitoneal (RP) mass. CT chest had a 3.6 cm subcarinal lymph node with infiltrating nodal tissue in the mediastinum. Bronchoscopy with endobronchial ultrasound (EBUS) showed a well circumscribed mass 3x2.5 cm with two echogenic densities and absent blood flow on doppler. On transbronchial needle aspiration (TBNA) of the mass, thick yellow and bloody fluid was aspirated, and noted to reaccumulate after aspiration. Studies were significant for cellular fluid (488 cells - 60% neutrophils), with a high amylase of 1,144 unit/L, lactate dehydrogenase greater than 3,600 unit/L, glucose less than 10 mg/dL and protein 5.6 g/dL. Cultures were negative. Cytology showed atypical (non-malignant) cells with necrotic debris. Magnetic resonance imaging (MRI) of the chest showed a 3.8x3.7 cm complex subcarinal cystic lesion with debris and absent enhancement. Subsequently, she underwent surgical resection of the mass with final pathology showing fibrous tissue with chronic inflammation and fibrinous exudate without definitive cystic lining. RP mass was found to be fibrosis. She is planned for a 6 month follow up CT to evaluate for recurrence. DISCUSSION: Our patient’s presentation, MRI findings, and fluid studies of the mass are highly suggestive of an esophageal duplication cyst although diagnosis is limited by the absence of epithelial lining on surgical pathology. Her age and RP mass made malignancy high on the differential. Other differential included bronchogenic cyst, hydatid cyst, necrotic lymphadenopathy, or malignancy. The RP fibrosis and cyst could suggest a systemic process. Our case is a unique instance of the use of EBUS-TBNA for diagnosis, highlighting the utility of bronchoscopy in evaluation of non-lymph node mediastinal masses. Studies have demonstrated the safety and high sensitivity of EBUS-TBNA to distinguish between malignant and non-malignant lesions. CONCLUSIONS: Esophageal duplication cysts often present as a mediastinal mass causing variable symptoms, including cough, shortness of breath, dysphagia, and chest pain. This patient had a rare presentation of this rare condition. This case demonstrates the utility of EBUS-TBNA in diagnostic evaluation of mediastinal masses, as imaging characteristics alone are not sufficient. Reference #1: Kolomainen et al. Esophageal duplication cyst: case report and review of the literature. Dis Esophagus. 2017 Nov 1;11(1):62-65. Reference #2: Sonthalia et al. Congenital Esophageal Duplication Cyst: A Rare Cause of Dysphagia in an Adult. Gastroenterology Res. 2016 Oct; 9(4-5): 79–82 Reference #3: Yang et al. Endobronchial ultrasound-guided transbronchial needle aspiration in the diagnosis of non-lymph node thoracic lesions. Ann Thorac Med. 2013 Jan-Mar; 8(1): 14–21. DISCLOSURES: No relevant relationships by Ankita Agarwal, source=Web Response No relevant relationships by Nicole Herbst, source=Web Response No relevant relationships by Abesh Niroula, source=Web Response No relevant relationships by Keriann Van Nostrand, source=Web Response