An application of ERBB2 receptor inhibitors in a rare case of S310F somatic ERBB2 mutation of primary signet-ring cell adenocarcinoma of vagina: A case report and review literature of S310F somatic ERBB2 mutation in breast and gynecologic cancers

•The extremely uncommon subtype of epithelial vaginal cancer.•Comprehensive genomic sequencing of the rare subtype vaginal cancer.•Incorporated of the actionable targeted drugs in the treatment of uncommon cancer based on the comprehensive genomic profile.•A promising response of uncommon disease after the actionable targeted therapy.