Analysis of KRAS, BRAF, and EGFR mutational status in respiratory epithelial adenomatoid hamartoma (REAH)

Background: Respiratory epithelial adenomatoid hamartoma (REAH) is a sinonasal glandular overgrowth arising from the surface respiratory epithelium and invaginating into the stroma. Clinically, it appears as a polypoid mass that may cause nasal obstruction, anosmia, and epistaxis. The presence of cartilaginous and/or osseous areas move the lesion to a chondro-osseous respiratory epithelial (CORE) hamartoma subtype. Scattered small seromucinous glands may be observed between typical REAH glands and when it is the only feature, it represents seromucinous hamartoma (SH). The molecular pathogenesis of REAH has been poorly explored and remains unclear. Given that KRAS, BRAF, and EGFR mutations have been detected in a variety of sinonasal tumors, we aimed to assess these mutations in REAH and SH.Methods: Ten REAH (including one CORE subtype), in addition to two SH cases, were Sanger sequenced by standard techniques. The targeted regions included KRAS exons 2-4 (encompassing hotspots codons 12, 13, 61, and 146), BRAF exons 11 and 15 (spanning the V600 codon), and EGFR exons 19 and 20. Results: All REAH and SH samples showed wild-type sequences for KRAS, BRAF, and EGFR genes.Conclusion: Our results demonstrate a lack of KRAS, BRAF, or EGFR pathogenic variants with further evaluation of REAH and SH needed to elucidate driver genetic events.