What is a mediastinal teratoma?
Teratomas are the most common mediastinal germ cell tumor, composed of tissues from more than one of the three primitive germ cell layers (teeth, skin, and hair from ectoderm; cartilage and bone from mesoderm; and bronchial, intestinal, or pancreatic tissue from endoderm). Most teratomas are well-differentiated and benign (mature). However, on rare occasions teratomas may contain fetal tissue and either recur or metastasize (when immature). Mediastinal teratomas occur most commonly in children and young adults. Although usually asymptomatic, large tumors may cause symptoms because of local mass effect. On imaging, mature teratoma appears as a lobulated, well-defined heterogeneous anterior mediastinal mass usually located to one side of the midline with fat attenuation or signal intensity foci, along with multilocular cysts, and very high attenuation/very low signal intensity teeth, calcifications, or bone. The presence of fat, fluid, and soft tissue elements within an anterior mediastinal mass is virtually diagnostic of a mediastinal teratoma. Surgical excision is curative.