Extralobar pulmonary sequestration with a cyst: a case report.

Extralobar pulmonary sequestration (EPS) is a congenital malformation. In contrast with intralobar sequestration, EPS located outside the normal lung tissue and with a distinct pleural covering. In the current case report, we present a rare case of EPS. To our knowledge, this is the first report of a cyst occurring within the EPS. A 17-year-old male patient presented with chest pain for 1 month. Computed tomography (CT) scan demonstrated a sharply circumscribed mass at the left side of the lower thoracic vertebrae. No aberrant vessel was observed on contrast-enhanced CT. The preoperative diagnosis was a posterior mediastinal tumor or EPS and surgical resection was recommended to the patient. During the operation, an extrapulmonary sequestration lobe was found in the left chest cavity. There was an aberrant artery connecting the sequestration lobe and the descending aorta. A cyst was located in the apex of the sequestration lobe. Surgical resection was performed via thoracoscopy. The postoperative histopathology confirmed an extrapulmonary sequestration combined with a cyst. The patient recovered successfully and was discharged on the sixth day postoperatively. He did not present with recurrent chest pain at the 6-month follow up. EPS should be considered when a posterior mediastinal conical mass is shown on chest CT.