The case of a young ethnic Chinese male who presented with rare ectopic thymic tissue in the middle mediastinum is reported and the related literature reviewed. The most common tumors found in the middle mediastinum are mediastinum cyst, bronchogenic cyst, lymphoma and pericardial cyst; most thymic tumors are found in the anterior-superior mediastinum area and less than 4% are found elsewhere. Ectopic thymic tumors in the middle mediastinum are the rarest. Computed tomography has high sensitivity and specificity for thymic tissue, and the gold standard treatment is radical resection. The World Health Organization histological grading and Masaoka staging system for thymoma remain the most important indicators for survival. (Thorac Med 2012; 27: 173-180)