A case of different EGFR mutations in surgically resected synchronous triple lung cancer.

We describe a 77-year-old Japanese woman who presented with three nodule shadows in three different lobes of the right lung, without evidence of lymph node metastasis or distant metastasis. All three tumors were surgically resected. The pathological diagnosis was synchronous multiple primary lung cancer: pT2aN0M0, pStageIB. Based on a differing epidermal growth factor receptor (EGFR) mutation status, no lymph node metastasis, and no distant metastasis, the tumors were characterized as synchronous triple primary rather than intrapulmonary metastases. At eight months after surgery, a new lesion emerged in the right lower lobe. Given that the most advanced tumor had an EGFR del-19 mutation, the patient was orally administered afatinib. Since then, the treatment response of the patient has been assessed as stable disease (SD) for about two years. This is a very rare case of resected triple synchronous primary lung cancer on the same lung side in which the lesions all had a different mutation status, and this report highlights the clinical utility of surgical resection of multifocal lung nodules without lymph node metastasis or distant metastasis in order to optimize therapy for patients with known driver mutations.