Clinical Benefit from Trametinib in a Patient with Appendiceal Adenocarcinoma with a GNAS R201H Mutation.

We report the case of a patient with appendiceal adenocarcinoma with mucinous peritoneal carcinomatosis who was treated with trametinib upon identification of a GNAS R201H mutation by comprehensive genomic profiling. The molecular pathology of appendiceal neoplasms is reviewed, and the mechanistic basis underlying the clinical benefit as well as the subsequent course on trametinib that were observed in this patient are discussed.