Complete remission following icotinib administration in an advanced ectopic thymic carcinoma patient harbouring the EGFR exon 19 deletion

Ectopic thymic carcinoma (TC) is an extremely rare disease with a poor prognosis. The main treatment for early TC is surgery, although an effective treatment for advanced TC is lacking.

We present the case of a 61-year-old man with advanced posterior mediastinum thymic squamous cell carcinoma. Amplification refractory mutation system (ARMS)-polymerase chain reaction (PCR) analysis was used to investigate the molecular and mutational characteristics of this tumour.

After chemotherapy and radiotherapy, the tumour showed disease progression. Immunohistochemistry revealed that the tumour was positive for CD117 (specific for primary TC), CK19, CD56 and Ki67. ARMS-PCR analysis revealed an EGFR exon 19 deletion in the patient. The patient subsequently received icotinib treatment and achieved complete remission for 3 years.

This case report suggests that tyrosine kinase inhibitors are a potential treatment strategy for patients with TC harbouring EGFR alterations.