Histological evolution from primary lung adenocarcinoma harboring EGFR mutation to high-grade neuroendocrine carcinoma.

Lung adenocarcinoma in eight patients transformed into high-grade neuroendocrine carcinoma and retained the original activating EGFR mutations after targeted therapy by TKIs. Furthermore, the prognosis of the transformed carcinoma was worse than the original primary genetic and morphologic type.