A CASE OF EXTRALOBAR PULMONARY SEQUESTRATION: POSTERIOR MEDIASTINAL HYPERVASCULAR CYSTIC LESION MIMICKING VASCULAR TUMOR

Hypervascular lesions in the posterior mediastinum can pose diagnostic challenges as they resemble various entities, including vascular tumors and neurogenic tumors. One frequently overlooked possibility is extralobar pulmonary sequestration (ELS), a congenital abnormality of non-functional lung tissue with blood supply from systemic arteries and venous drainage to the systemic venous system. This study aims to report a case of ELS in an adult patient that radiologically resembled a vascular mediastinal tumor. The research done by using case study with clinical evaluation, imaging using contrast-enhanced MSCT thorax, and histopathological confirmation. The outcomes of
this study are that an asymptomatic adult patient was found to have a hypervascular cystic mass in the posteroinferior region of the left lower lobe with blood supply from the left posterior intercostal artery and drainage to the azygos and hemiazygos venous systems. No connection with bronchial branches was observed. Histopathological imaging reinforced the ELS diagnosis. From the findings it can be concluded that ELS diagnosis should be considered in cases of hypervascular posterior mediastinal masses, especially those with vascular supply from systemic arteries and without bronchial communication. Contrast-enhanced thoracic MDCT examination is crucial for establishing diagnosis, preventing unnecessary invasive procedures, and supporting appropriate management.