SESSION TITLE: Wednesday Fellows Case Report Posters SESSION TYPE: Fellow Case Report Posters PRESENTED ON: 10/23/2019 09:45 AM - 10:45 AM INTRODUCTION: In an era of increasing advancements in interventional pulmonology, lung transplantation, and robotic thoracic surgery, an awareness and understanding of congenital airway anomalies is vital. CASE PRESENTATION: A 63 year-old woman with a history of rheumatoid arthritis, Sjogren’s syndrome, and latent TB was referred to pulmonary clinic for worsening bronchiectasis and tree-in-bud nodularity seen on a chest CT scan. A bronchoscopy was performed, and during the initial inspection, an unexpected orifice was noted just distal to the right upper lobe takeoff. 3-D reconstruction of her chest radiographs (Fig. 1) revealed an ectopic airway originating from the lateral wall of the bronchus intermedius, consistent with a rare anatomic anomaly called a “right posteparterial bronchus.” DISCUSSION: Over 500,000 bronchoscopies are performed annually in the United States [1], and most of them reveal normal airway anatomy in the classic distribution described by Jackson and Huber in 1943. However, in rare instances, anomalous bronchi may be encountered, which can lead to erroneous reporting and sampling of the wrong lobe. Furthermore, if lung transplantation or surgical resection is planned, an accurate description of the existing airways is crucial. Finally, ectopic tracheal bronchi may be occluded during intubation, which can lead to inadvertent atelectasis, pneumothorax, or respiratory failure [3]. Therefore, it is important for the adult bronchoscopist to be aware of these possible anatomic variants. One of the most common anomalies described in the literature is the tracheal bronchus which arises from the trachea and supplies ventilation to a significant proportion of the upper lobe. It is often times called a “pig bronchus” because the normal anatomy of swine consists of an upper lobe bronchus originating from the trachea. [1] As for the others, naming of an anomalous bronchus depends on the relationship of its origin to the location of the pulmonary artery (PA) and upper lobe (UL) takeoff. An anomalous bronchus arising from the main bronchus above the level of the PA is referred to as eparterial, and those which originate below the level of the PA are termed hyparterial. For a bronchus on the right that arises below the RUL bronchus but is still above the level of the PA, this is termed posteparterial. On the left side, as the origin of the LUL bronchus is below the level of the PA, an anomalous bronchus arising below this is termed posthyparterial, while a bronchus that appears just above it is termed prehyparterial [4]. CONCLUSIONS: In our patient, she had a right posteparterial bronchus which was asymptomatic and incidentally found. This anomaly has an incidence of approximately 0.9%. Although rarely seen, a thorough understanding of congenital airway anomalies should be part of every adult bronchoscopist’s education. Reference #1: Mehta A, et al. Chest 2015; 148: 274-287 Reference #2: Chassagnon G, et al. Radiographics 2016; 36: 358-373 Reference #3: Wooten C, Clinical Anatomy 2014; 27: 1223-1233 DISCLOSURES: No relevant relationships by Ching-Fei Chang, source=Admin input No relevant relationships by Gregory Grandio, source=Web Response No relevant relationships by Christopher Lee, source=Web Response