[Mature teratoma in the posterior mediastinum showing the fatty density on the chest computed tomography].

We reported a case of posterior mediastinal mature teratoma. A 16-year-old woman was referred for further investigation of a left paravertebral mass detected on chest roentgenogram. The defined mass was located above the diaphragm and showed homogeneous fat density on computed tomography (CT) and hypersignal intensity on both T1 weighted images and T2 weighted images on magnetic resonance imaging (MRI). Radiologically, there was a mimicking foci of calcification. The mass was histologically diagnosed as mature teratoma.