The imaging features of mediastinal teratoma are mainly bone and tooth shadows within the tumor on X-ray or fat and fluid interfaces on chest CT. On conventional X-ray, mediastinal teratomas usually appear round, ovoid, or lobulated in the case of multicystic tumors. The contour of the tumor is clear and smooth, while some dermatoid cysts are slightly irregular due to secondary infection, surrounding inflammatory adhesions and pleural thickening. Bone and tooth shadows are seen within the tumor as a characteristic manifestation of this type of tumor. If the tumor increases significantly in a short period of time it should be considered malignant, and malignant tumors are more often solid. Chest CT may reveal a predominantly fat-dense mass containing calcified solid nodules, or a mass with a combined fluid component. In this case, the fat portion resides above and the fluid portion is below. There is a fat-fluid surface between the two, and rounded shadows of mixed density in the form of lines or cords are seen as hair clusters at this interface. When the tumor has secondary infection surrounded by inflammatory adhesions and pleural thickening, its outline is blurred. If patients find mediastinal teratoma, it is recommended to go to regular hospital for further consultation and treatment as soon as possible.