Case Report: Chemoimmunotherapy in microsatellite-instability-high advanced goblet cell carcinoma of the colon

Background Mismatch repair (MMR) deficiency is a fundamental factor affecting the management treatment outcomes of colorectal cancer (CRC). MMR status can be diagnosed by both immunohistochemistry (IHC) polymerase chain reaction (PCR). Since tumors with are prone to respond immunotherapy immune checkpoint inhibitors used treat such tumors. Case presentation A 69-year-old male patient presented an outside clinic weight loss and abdominal pain. Radiological investigations detected mesenteric mass 10 cm, peritoneal implants, mediastinal lymphadenopathy. The eventual biopsy result from was mucinous adenocarcinoma goblet cell pattern. IHC unclear for in mismatch (dMMR) metastatic CRC (mCRC), diagnosis confirmed PCR. received 8 cycles FOLFIRINOX + bevacizumab followed FOLFOX combined pembrolizumab. No adverse effect reported related which resulted radiologic metabolic regression. underwent cytoreductive surgery hyperthermic intraperitoneal chemotherapy (HIPEC). final pathology results revealed pathological complete response R0 resection. In 6 th month follow-up, no recurrence or metastasis reported. Conclusion Chemotherapy combination promising modality also mCRC. This index case who colon pattern had pCR.