title: Concomitant T790M mutation and small-cell lung cancer transformation after acquired resistance to epidermal growth factor receptor-tyrosine kinase inhibitor.
abstract: A 70-year-old man was admitted to our hospital with an abnormal chest X-ray shadow. Bronchoscopy revealed an adenocarcinoma tumour with an epidermal growth factor receptor (EGFR) exon 19 deletion. Positron emission tomography-computed tomography scanning and magnetic resonance imaging showed advanced stage IV lung cancer. He was treated with erlotinib as a first-line drug, which maintained a clinical response for 16 months. After disease progression, a re-biopsy was done from the tumour in the right lower lobe. The obtained specimen harboured both small-cell lung cancer (SCLC) transformation with retention of the EGFR 19 deletion and the development of an EGFR T790M mutation. We came across a very rare condition of concomitant T790M mutation and SCLC transformation after acquired resistance to EGFR-tyrosine kinase inhibitor.
authors.affiliation: Division of Respiratory Medicine National Hospital Organization Kyoto Medical Center Kyoto Japan.
authors.forename: Kohei
authors.initials: K
authors.lastname: Fujita
authors.affiliation: Department of Respiratory Medicine Graduate School of Medicine, Kyoto University Kyoto Japan.
authors.forename: Young Hak
authors.initials: YH
authors.lastname: Kim
authors.affiliation: Department of Diagnostic Pathology Graduate School of Medicine, Kyoto University Kyoto Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Yoshizawa
authors.affiliation: Division of Respiratory Medicine National Hospital Organization Kyoto Medical Center Kyoto Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Mio
authors.affiliation: Department of Respiratory Medicine Graduate School of Medicine, Kyoto University Kyoto Japan.
authors.forename: Michiaki
authors.initials: M
authors.lastname: Mishima
keywords: Adenocarcinoma; T790M mutation; epidermal growth factor receptor‐tyrosine kinase inhibitor; small‐cell lung cancer transformation