Posterior mediastinal extralobar pulmonary sequestration misdiagnosed as a neurogenic tumor: A case report

Pulmonary sequestration-both intralobar and extralobar-is a rare congenital developmental malformation. Extralobar pulmonary sequestrations (EPS) have their own pleura but are separated from the bronchus and usually occur in the left lung. They are mainly found mainly between the lower lobe and the mediastinum. EPS is rarely found within the mediastinum itself, even rarer so in the posterior mediastinum.

We report the case of a 27-year-old man who was misdiagnosed with a neurogenic tumor based on preoperative contrast-enhanced computed tomography (CT) and magnetic resonance imaging findings. Contrast-enhanced chest CT revealed a posterior mediastinal mass measuring 1.2 cm × 1.4 cm × 3.3 cm, which consisted of some cystic areas and showed slight enhancement. The mass was in the 11^th paravertebral region and attached to the 11^th thoracic vertebra behind the descending aorta in the posterior mediastinum. An arteriole originating from the intercostal artery and a vein originating directly from the hemiazygos vein were found in the pedicle of the mass. The mass was resected in a uniport video-assisted thoracoscopic surgery. During the operation, the pyramid-shaped mass appeared well-encapsulated. Postoperative histopathology established a diagnosis of EPS. One month later, a follow-up CT of the thorax showed good recovery.

Although EPS rarely occurs in the posterior mediastinum, its diagnosis should be considered when posterior mediastinal tumors are suspected.