Abstract
A 72-year-old woman underwent complete video-assisted thoracic surgical procedure for removal of a smooth, progressively contrasted, homogeneous 20-mm nodular anterior mediastinal tumor. The tumor was completely resected. The pathologic diagnosis was malignant melanoma, which was positive for HMB-45 and S-100. Postoperative positron emission tomography revealed no other lesions throughout the whole body. The tumor was therefore diagnosed as primary malignant melanoma of the thymus. The patient's postoperative course was good, and she had no recurrence. This tumor is reportedly highly malignant and prone to recurrence; hence, careful follow-up is necessary for this case.