Thymic epithelial tumors: what's next?

Thymic epithelial tumors (TETs) are rare malignancies arising in an organ central to T cell development and immune tolerance, creating a distinctive interface between tumor biology and immunotherapy. Complete surgical resection remains the mainstay for resectable disease, whereas systemic treatment options for unresectable, recurrent, and metastatic TETs remain limited. The unique immunobiology of thymoma, particularly impaired central immune tolerance, may account for the unusual balance between antitumor activity and severe immune-related adverse events observed with immune checkpoint blockade. Recent molecular and immune profiling has begun to reveal biologically distinct TET subtypes and potential therapeutic vulnerabilities, including alterations in cell-cycle, PI3K/AKT/mTOR, RTK/RAS/MAPK, and DNA damage-response pathways, as well as epigenetic and immune regulatory mechanisms. Emerging strategies, including antibody-drug conjugates and biomarker-informed targeted and immune therapies, may expand systemic treatment options for advanced disease. This review examines these developments in the context of the distinctive biology of the thymus and highlights the key unanswered questions that may shape the next generation of TET research and treatment.