Rare BRCA2 Mutation and MSI-H in Male Patient with Aggressive Stage III Colorectal Cancer, Case Report and Literature Review.

Colorectal cancer is the third most common malignancy worldwide. We report the case of a 66-year-old man diagnosed with stage III B colorectal cancer who underwent radical surgery, adjuvant chemotherapy and subsequently developed hepatic metastases. Two months following metastasectomy, PET-CT scan revealed liver metastases with metabolic activity. The patient was started on FOLFIRI chemotherapy regimen in combination with cetuximab, and achieved stable partial remission 7 weeks after starting the treatment. NGS and IHC testing of the surgically removed tumor revealed MSI-H/dMMR, and NRAS/KRAS wild type status, moderate positive (30%) expression of PD-L1 protein, along with BRCA2 mutation.