Right Epipericardial Fat Necrosis After Thymectomy.

A 62-year-old male patient underwent median sternotomy and thymectomy for thymoma (World Health Organization classification type B1+B3, Masaoka classification stage II). A 10-month follow-up postoperative computed tomography showed a 22-mm nodule in the anterior mediastinal lipid tissue just above the right diaphragm. The patient was followed for 8 years, and the nodule's capsule eventually became calcified. Considering the possibility of postoperative recurrence of thymoma, we excised the nodule. The pathologic diagnosis was epipericardial fat necrosis. In some cases, fat necrosis is difficult to distinguish from malignancy by imaging only; surgical resection has diagnostic significance and should be considered.