Images in Clinical Medicine

Benign Mediastinal Teratoma

Lisa M. Jones, M.D., and David A. Bradshaw, M.D.

N Engl J Med 2008; 359:841August 21, 2008

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Article

A 23-year-old male Marine recruit passed out while bending over after a 2.4-km (1.5-mile) run. Chest radiography showed a mass in the anterior mediastinum (Panel A, arrow). His medical history was notable only for the removal of a benign thyroid cyst at the age of 12 years. He reported no use of medications or tobacco and no drug allergies. The physical examination and initial laboratory studies were unremarkable except for prominent varicosities noted on his chest (Panel B). Contrast-enhanced computed tomography of the chest revealed a large anterior mediastinal mass with fluid, fat, and calcific densities (Panel C, arrow) that was compressing the right pulmonary artery (Panel D, arrow). Collateral circulation in the chest wall was noted (Panels C and D, arrowheads). Important causes of an anterior mediastinal mass include thymoma, teratoma, thyroid tissue, and lymphoma. The anterior mediastinal mass was resected, and a benign teratoma with components of all three germ-cell layers was diagnosed on pathological evaluation. The patient subsequently made a full recovery and returned to serve in his unit.

Lisa M. Jones, M.D.
David A. Bradshaw, M.D.
Naval Medical Center San Diego, San Diego, CA 92134-1005