Recalcitrant thyroid eye disease responsive to targeted EGFR inhibition in a patient with lung adenocarcinoma: a case report

Thyroid eye disease (TED) is an autoimmune disorder targeting periorbital tissue with potentially devastating effects. Treatment options for TED are limited and have side effects that prohibit their use in certain patients. As such, there is increasing interest to identify new therapeutic targets. We report a case of long standing and refractory thyroid eye disease that was responsive to targeted epidermal growth factor receptor (EGFR) inhibition with osimertinib. The patient presents with Graves disease and thyroid eye disease diagnosed 2 years prior and previously treated with steroids and teprotumumab. Her TED reactivated and was unresponsive to oral steroids. Five months later she was diagnosed with lung adenocarcinoma and began targeted EGFR inhibition with osimertinib. Notably, her TED symptoms rapidly improved. Following the completion of a course of osimertinib, her TED reactivated but again rapidly improved after resuming osimertinib. This case highlights EGFR as a potential novel therapeutic target in TED.