B47-43 The Left Lung on the Right: Bronchoscopic Challenges in a Patient With Situs Inversus Totalis

Abstract Introduction Situs Inversus Totalis (SIT) is a rare congenital condition characterized by complete mirror-image transposition of thoracic and abdominal organs. While often asymptomatic and discovered incidentally, SIT poses unique diagnostic and procedural challenges, particularly during bronchoscopic evaluation where spatial orientation and anatomic landmarks are reversed. Case Description A 66-year-old female with known SIT, Sjogren’s disease and chronic kidney disease was admitted to the hospital for worsening shortness of breath. CT chest was obtained on admission and noted SIT as well as patchy peripheral consolidative and ground glass opacities predominantly in the right lower lobe, a 1.8-cm left upper lobe cavitary lesion and left middle lobe bronchiectasis. The patient was started on appropriate treatment and our pulmonary team was consulted for the evaluation of the above findings. Flexible bronchoscopy was performed using standard techniques under moderate sedation. Upon entering the trachea, the expected right and left bronchial anatomy was reversed, with the right mainstem bronchus angling more horizontally and the left bronchial tree demonstrating the branching pattern typically seen on the right. Sequential inspection confirmed the reversed segmental anatomy. A bronchoalveolar lavage (BAL) was performed of the left middle lobe with bronchial brush of the right lower lobe. Navigation and sampling were guided by pre-procedural imaging to ensure accurate localization and to avoid laterality errors. The BAL fluid was clear, and microbiologic studies, including bacterial, fungal, and mycobacterial cultures, were negative. Cytologic evaluation showed no evidence of malignant cells. The patient tolerated the procedure well without complications. Discussion Situs Inversus Totalis is a rare congenital condition, with an estimated prevalence of approximately 1 in 8,000 to 1 in 25,000 live births. SIT is typically discovered incidentally, as many affected individuals are asymptomatic unless associated with other anomalies such as congenital heart disease or primary ciliary dyskinesia. The condition is considered rare in clinical practice and may present unique challenges in surgical and diagnostic procedures due to mirror-image anatomy. Standard bronchial anatomy, procedural planning, and even electronic navigation systems may require adjustment to account for reversed orientation. Awareness of such anatomic variations enhances procedural safety and serves as a valuable learning experience for trainees to develop adaptable spatial orientation skills to avoid sampling from the wrong lung. This case highlights the importance of reviewing imaging prior to bronchoscopy, using detailed airway mapping, and maintaining situational awareness during the procedure. This abstract is funded by: none