Successful Resection of G719X-Positive Pleomorphic Carcinoma after Afatinib Treatment

We report a case of pleomorphic carcinoma with exon 18 mutation (G719X) of the epidermal growth factor receptor (EGFR), which showed good response to afatinib and resulted in successful resection. To our knowledge, this is the first report on the use of afatinib for pleomorphic carcinoma followed by the surgical resection. The patient was a 59-year-old woman, who visited our hospital because chest computed tomography showed a 28 × 28-mm nodule in the left upper lobe. Bronchoscopy was performed and the histological findings of transbronchial biopsy revealed adenosquamous carcinoma positive for G719X mutation in exon 18 of the EGFR. Since fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography revealed a positive accumulation in the bilateral hilar and mediastinal lymph nodes, the disease was diagnosed as cT1bN3M0, stage IIIB. After 3 months of afatinib therapy, FDG accumulation in primary tumor was almost gone. However, FDG accumulation in lymph nodes remained unchanged. Video-assisted thoracic surgery was planned for further diagnostic information and left upper lobectomy with mediastinal lymph node dissection was performed. The resected tumor included adenocarcinoma, squamous cell carcinoma, and spindle cell components, without lymph node metastasis. Thus, the disease was diagnosed as pleomorphic carcinoma (pT2aN0M0, stage IB). All components in the resected specimen had the same G719X mutation in exon 18 of the EGFR. The patient has shown no signs of recurrence at 1 year after the operation. The present case indicates the possibility of minor EGFR mutations in pleomorphic carcinoma and successful outcome by the use of afatinib and surgical resection.