Thymomas are epithelial neoplasms that originate from the epithelial component of the hematopoietic gland, and currently there is not an agreement about their classification. Despite the recent publication by the WHO, most pathologists do not follow the proposed grouping due to the impracticality of it. In addition, the treatment of these tumors largely depends on the experience of the surgeon/oncologist and also on the institution in which these patients are cared for. More and more patients come to large medical centers, which have the experience in dealing with these patients. The topics covered include pathologic staging, clinical management, surgical management, radiologic approaches, and evidence-based medicine. This subject is extremely important and highly relevant in today's medical practice.