Near Total Regression of Diffuse Brain Metastases in Adenocarcinoma of the Lung with an EGFR Exon 19 Mutation: A Case Report and Review of the Literature

We report the case of a woman with diffuse brain metastases from lung cancer who experienced total regression of the metastases under gefitinib treatment. The 58-year-old woman was referred to our hospital with a complaint of severe headache. A brain MRI revealed diffuse metastatic lesions in the cerebra and cerebellum. Adenocarcinoma of the lung with multiple brain metastases was diagnosed. The tumor was positive for an epidermal growth factor receptor (EGFR) exon 19 deletion mutation. She was treated with gefitinib 250 mg per day. One year later, the diffuse brain metastases had totally resolved. EGFR-tyrosine kinase inhibitor therapy could be a first-line treatment for patients with advanced adenocarcinoma of the lung with EGFR mutation, especially in those with brain metastases.