Prognostic impact of lynch syndrome in signet-ring cell carcinoma: A case report and review

Abstract

Signet ring cell carcinoma (SRCC) is a rare subtype of colorectal cancer with distinct molecular features and aggressive behavior compared to adenocarcinoma. Most cases are diagnosed at an advanced stage with poor prognosis. SRCC is often associated with CpG island methylation phenotype (CIMP)-high, high (Methylation) BRAF mutations, but their prognostic role is unclear. We report a 57-year-old male with locally advanced sigmoid SRCC and germline Lynch syndrome (pathogenic MLH1 mutation). Despite the advanced stage, he has shown excellent response to adjuvant 5-fluorouracil chemotherapy, unlike typical SRCC outcomes. This case highlights the need to determine the prognostic and predictive significance of lynch syndrome in colorectal SRCC. Identifying patients with improved chemotherapy sensitivity in lynch Syndrome could treatment and improve survival in this rare histological subtype.