Thymoma is the most common mediastinal tumor in adulthood. By definition, it is a thymic epithelial neoplasm that displays at least some characteristics of normal thymus. Microscopically it comprises an admixture of thymic epithelial cells and immature T lymphocytes in various proportions and demonstrates marked intratumoral heterogeneity, which results in several histological subtypes. Recent studies have shown that thymoma is a neoplasm of at least low malignant potential and its prognosis mainly depends on disease stage and resectability status. Despite a controversy regarding histological subtype and its clinical relevance, recent data have shown that certain thymoma histological classifications might have a role in predicting survival and prognosis. The aim of this review will be an overview concept of thymomas that is intended to be informative and practical for daily surgical pathology practice. Particular emphasis is paid to the latest developments in the disease staging systems, histological classifications and specimen handling and reporting guidelines.