Frequent BRAF or EGFR Mutations in Ciliated Muconodular Papillary Tumors of the Lung

IntroductionCiliated muconodular papillary tumors (CMPTs) are recently characterized, rare peripheral nodules of the lung. These small tumors are histologically comprised of a vaguely organized mixture of nonatypical ciliated columnar cells, mucous cells, and basal cells, and consistently follow a benign clinical course. However, the histogenesis of CMPTs remains uncertain.MethodsWe performed detailed genomic analyses of 10 archived CMPT cases, using next-generation sequencing and high-resolution melting analysis.ResultsMutations were identified in eight of the 10 cases (80%); four cases harbored the BRAF-V600E mutation, one case harbored the BRAF-G606R mutation, and three cases harbored deletions in exon 19 of EGFR. All of the deletions in EGFR were of the E746-T751/S752V subtype.ConclusionsThe high prevalence of driver gene mutations in CMPTs supports the notion that these lesions are neoplastic rather than reactive or metaplastic.