[Anterior Mediastinal Dermoid Cyst with Enlarging Tendency:Report of a Case].

A 36-year-old woman referred to our hospital for treatment of a mediastinal tumor. Contrast computed tomography (CT) scan was revealed a 31×21×25 mm mass in the anterior mediastinum, with low contrast, clear border, and a tendency to increase. On magnetic resonance imaging( MRI) examination, the anterior mediastinal tumor showed homogeneous high signal intensity on T1-weighted images and a combination of high and low signal intensities on T2-weighted images. A benign tumor was suspected, and surgery was performed for diagnostic and therapy. Histopathology did not demonstrate malignant cells and we diagnosed the tumor as dermoid cyst. The postoperative course was uneventful and the patient was discharged on 2nd postoperative day.