Synchronous driver gene alterations (EGFR L858R, T790M, and ROS1) rearrangements in a patient with early-stage lung adenocarcinoma

Concurrent EGFR mutation and ROS1 rearrangement is a rare event in early-stage non-small-cell lung cancer. In addition, a co-occurring de novo EGFR T790M mutation in such a case is extremely rare. We encountered a 72-year-old woman who developed 3 early-stage lung lesions synchronously, one each harboring EGFR L858R, ROS1 rearrangement, and EGFR L858R and de novo T790M. These three nodules were pathologically time-matched lepidic predominant adenocarcinoma with small invasive lesions, which may reflect the concept of field cancerization with driver mutations.