Multimodal therapy including cytoreductive surgery and serplulimab may manage non-signet-ring cell ovarian metastasesNew Treatment Strategy Shows Promise for Rare Colorectal Cancer Case

BackgroundColorectal cancer (CRC) metastasizes to the ovary in approximately 0.8–7.4% of cases, typically indicating aggressive biology and poor prognosis. Metachronous bilateral ovarian involvement with spontaneous rupture is exceptionally rare, and the distinction between signet-ring cell (Krukenberg) and non-signet-ring cell metastases carries prognostic significance.Case presentationWe present a 54-year-old female who underwent laparoscopic right hemicolectomy for pT4aN0M0 ascending colon adenocarcinoma, followed by eight cycles of adjuvant XELOX chemotherapy. Nineteen months later, imaging revealed huge pelvic cystic-solid masses with diffuse peritoneal thickening. Intraoperatively, spontaneous rupture of the mass (~14 cm) with active bleeding and hemorrhagic ascites was found, along with extensive miliary peritoneal seeding. The patient underwent bilateral salpingo-oophorectomy, omentectomy, and HIPEC catheter placement. Pathology confirmed bilateral ovarian metastatic adenocarcinoma of colorectal origin with no signet-ring cells, excluding a true Krukenberg tumor. Genetic testing revealed NRAS p.G12D mutation and high tumor mutational burden (TMB-H). She subsequently received six cycles of XELOX chemotherapy with bevacizumab and serplulimab (anti-PD-1), achieving stable disease.ConclusionThis case demonstrates that non-signet-ring cell ovarian metastases can be equally aggressive, manifesting as spontaneous rupture after standardized therapy. For T4a CRC patients with serosal invasion, vigilant surveillance for ovarian and peritoneal metastasis is warranted. The multimodal strategy of cytoreductive surgery, HIPEC, and genotype-directed immunotherapy may offer a promising salvage approach in this challenging setting.