Malignant teratoma is a type of cancer that involves cysts that contain one or more of the three main types of cells found in a developing baby (embryo). These cells are callled ectoderms, mesoderms, and endoderms.
Malignant teratoma occurs most often in young men in their 20's - 30's. It is often located in the anterior mediastinum (in the chest). Most malignant teratomas have spread (metastasized) by the time of diagnosis and they can spread throughout the body.
A number of other cancers are often associated with these tumors including: