Extralobar sequestration in anterior mediastinum with pericardial agenesis.

We report a very rare case of extralobar sequestration and pericardial agenesis in a 22-year-old man. A computed tomographic (CT) scan demonstrated an anterior mediastinal mass. No aberrant artery was preoperatively identified. The patient underwent surgery with an impression of thymoma. An extralobar sequestration receiving its blood supply from the left pulmonary artery, accompanied with pericardial agenesis, was noted at the time of operation. The anterior mediastinum is an unusual site for extralobar sequestions. It is recommended to include extralobar sequestration in the differential diagnosis of anterior mediastinal masses, even if the aberrant artery is not recognized on the computed tomographic scan.