Summary

Teratomas are benign germ-cell tumors that occur in infants through young adults. They contain cell types from at least 2 of 3 primitive germ cell layers. Ectodermal elements often predominate (hair, skin, sweat gland, or tooth-like structures), as well as mesodermal (fat, cartilage, smooth muscle, bone) or endodermal (respiratory and intestinal epithelium) elements. Pericardial teratomas most commonly arise in the anterior superior mediastinum. These tumors usually are diagnosed in infants and children <10 months of age at a rate of 5 to 6 per 10,000 children. They are exceptionally rare in adults.