Metastatic Unfunctional Pancreatic Neuroendocrine Tumor in Lynch Syndrome

ABSTRACT Lynch syndrome (LS), a well‐known cancer risk syndrome, is caused by deleterious germline mutations in the mismatch repair genes. LS predispose patients to various types of cancers including colon adenocarcinoma. We discuss the case of a woman with LS who also developed a non‐functioning pancreatic neuroendocrine tumor (P‐NET) following primary colon adenocarcinoma. Multiple liver lesions were discovered 6 months following surgical excision the pancreatic mass and were later determined to be a neuroendocrine tumor. Liver lesions shrank after treatment with octreotide and Lutetium‐177 vipivotide tetraxetan. She is in remission and takes positron emission tomography scans every 6 months for monitoring. This case highlights the importance of LS genetic testing, the function of microsatellite instability (MSI) as a screening marker, and the need for additional study on the relationship between LS and P‐NETs, particularly through advanced molecular testing to confirm lesion relationships. The role of microsatellite instability (MSI) as a screening marker, and personalized treatment approaches like immunotherapy for dMMR tumors. Understanding these correlations may assist in early discovery, surveillance, and customized treatment for patients dealing with LS‐associated malignancies.