Fibroblast growth factor receptor 2 mutation-guided targeted therapy with lenvatinib in sebaceous carcinoma of the external auditory canal: a case report and literature review

This is the first global report of a successful case of lenvatinib treatment for a rare sebaceous carcinoma originating in the external auditory canal. The patient experienced local recurrence and pulmonary metastasis despite undergoing surgery and radiotherapy. Initial chemotherapy combined with immune checkpoint inhibitors achieved short-term stability, but the disease eventually progressed. Genetic testing revealed an Fibroblast growth factor receptor 2 (FGFR2) mutation, leading to a switch to targeted therapy with lenvatinib combined with capecitabine, demonstrating the value of targeted therapy in the management of rare, refractory sebaceous carcinoma.