Malignant mediastinal teratoma in a 15-year-old girl.

A well-differentiated anterior mediastinal teratoma was removed from the right hemithorax of a 15-year-old girl presenting initially with ascites. Death followed a precipitous clinical deterioration from widespread sarcomatous metastatic disease. The true malignant nature of this tumor was not apparent on initial resection and evaded detection until shortly before death. These unique features prompted a review of the pertinent literature on malignant mediastinal teratoma in children. A similar case had not been reported previously.