The most common mutations are in-frame deletions in exon 19 and point mutations in exon 21. Cases with classical mutations show a good response to EGFR tyrosine kinase inhibitors (TKIs), the standard first-line treatment. With the development of next generation sequencing, some uncommon genomic mutations have been detected. However, the effect of TKIs on such uncommon mutations remains unclear.

Here, we report a case of rare co-mutation in non-small cell lung cancer and the efficacy of afatinib on this co-mutation. A 64-year-old woman was diagnosed with thoracolumbar and bilateral local rib bone metastases, bilateral pulmonary nodules, and pericardial and left pleural effusion. The pathological diagnosis was lung adenocarcinoma. To seek potential therapeutic regimens, rare co-mutation comprising rare mutations and amplification were identified. The patient experienced a significant clinical response with a progression-free survival of 17 mo.

A case of non-small cell lung cancer with rare / mutations and amplification responds well to TKI treatment.