The differential diagnosis of anterior mediastinal tumors in CT

Objective To study the specific CT features in order to distinguish the common anterior mediastinal tumors.Methods 73 chest CT studies with pathological diagnosis of thymoma(n=37),mediastinal germ cell tumor(n=17) and lymphoma(n=19) were retrospectively reviewed by two radiologists who were blind to the pathological results.The CT findings of fat,cyst and calcification within the lesion,contrast enhancement,associated intrathoracic findings such as mediastinal invasion and lymph node enlargement were evaluated.Results Fat density within the mass was present in 58.8% with germ cell tumor,which was significantly higher than other anterior mediastinal tumors(P0.001).The presence of associated mediastinal lymphadenopathy was significantly found in lymphoma(73.7%) compared to other tumors(P0.001).The other CT findings showed no significant difference among these diseases(P0.05).Conclusion The CT findings that help in giving specific diagnosis of anterior mediastinal tumors which are fat attenuation and associated mediastinal lymphadenopathy.The presence of fat attenuation is highly suggestive of germ cell tumor and anterior mediastinal mass associated with mediastinal lymphadenopathy elsewhere is indicative of lymphoma.