Spectrum of Findings Seen in Patients With IDH1/2-Mutant Cholangiocarcinoma

Background: Cholangiocarcinoma-with a growing incidence rate and poor prognosis-is not an uncommon cancer. Molecular profiling can reveal actionable aberrations in at least a third of the tumors. This is especially so in the case of intrahepatic cholangiocarcinoma (ICC), where mutations in the isocitrate dehydrogenase 1 and 2 genes (IDH1/2) make up 15%-20% of these tumors. IDH1/2 mutant ICC is a rare disease that has not been adequately reported. To expand the spectrum of findings seen in these patients, we present a single institution case series. Methods and results: We descriptively characterize the clinical, radiological, and histopathological findings of 12 such patients. IDH1/2 mutant ICC was found in elderly women, with two-thirds of patients having additional co-mutations. Anecdotally, patients who did receive systemic and/or locoregional therapies had long-term durable outcomes. Conclusion: Our findings indicate an increasing need to personalize an approach for these patients with specific molecular alterations. With the advent of the IDH1 inhibitor ivosidenib and other inhibitors in this space, IDH1/2 mutation have both prognostic and predictive value. Our series builds upon the patterns and findings seen in these patients.