The thymus is the primary lymphoid organ designated to the adaptive humoral immunity construction. It guarantees immune self-tolerance by operating the positive and negative selection of the T cells during their development and maturation, avoiding autoimmune manifestations. Thymic epithelial tumors (TETs) are malignancies originating from the epithelial cell network of the thymus. In most cases, TETs are characterized by a good prognosis and their aggressiveness reflects the histopathological subtypes defined in the guidelines of the World Health Organization.
The malignancies of the thymus are a very rare form of mediastinal tumors, in particular, the neuroendocrine forms. Immunotherapy can lead to serious autoimmune complications in TET patients, and is therefore considered only in some cases of thymic carcinomas (TCs). TETs are programmed death-ligand 1 (PD-L1) expressing tumours.
