Asymptomatic paraganglioma of the posterior mediastinum misdiagnosed until operation.

A 23-year-old female patient was treated for a posterior mediastinal tumor of unknown histology. Her systemic blood pressure increased rapidly to a critical level immediately after starting surgical manipulation of the tumor, which was suggestive of a hyperfunctioning pheochromocytoma. The tumor was removed after controlling the blood pressure and was histologically diagnosed as an extra-adrenal pheochromocytoma. Further postoperative investigations showed the tumor to be a sporadic type through further postoperative investigations and the patient had subsequently an uneventful course.