Mucinous borderline ovarian tumour with concurrent germline WRN and somatic KRAS mutations: a case report

We report the case of a 52-year-old woman who presented with a large pelvic mass, which was surgically removed and diagnosed as a mucinous borderline ovarian tumour (MBT) of intestinal type. Comprehensive genomic testing revealed two significant alterations: a pathogenic germline WRN stop-gain variant (NM_000553.4:c.1105C>T, p.Arg369Ter; exon 9/35) and a somatic KRAS mutation (c.35G>T, p.Gly12Val). The coexistence of these findings suggests that inherited impairment of DNA repair mechanisms, which, together with acquired activation of the RAS pathway, may have cooperated in driving tumour formation. Functionally, loss of WRN activity could have promoted genomic instability, allowing the emergence of oncogenic KRAS activation as a secondary event. The patient underwent a total hysterectomy with bilateral adnexectomy. Histopathological examination confirmed an intestinal-type MBT without stromal invasion. This case illustrates how integrating germline and somatic analyses can uncover the molecular interplay between inherited predisposition and tumour evolution, offering valuable information for personalised risk assessment, family counselling, and long-term clinical surveillance.