Fluoropyrimidine Cardiotoxicity With Overlapping Vasospastic and Pericardial Features: A Diagnostic Challenge

Viñas-Mendieta A.E.; Valencia-Hernandez H.A.; Ruiz-Mori E.; Gonzalez-Trejo A.; Nieto-Dolores A.K.; Garcia-Cardenas M.; Dominguez-Linares A.; Espinola-Zavaleta N. · JACC: Case Reports (2026) · DOI: 10.1016/j.jaccas.2026.108330

Resumen

Background: Fluoropyrimidines are widely used in gastrointestinal malignancies but may produce cardiotoxicity, most commonly coronary vasospasm and rarely inflammatory pericardial involvement. Case Summary: A 57-year-old man with HER2-positive gastric cancer receiving FOLFOX-6M (leucovorin calcium-FOLinic acid, Fluorouracil and OXaliplatin) plus trastuzumab developed severe chest pain during a 5-fluorouracil (5-FU) infusion. The initial electrocardiogram showed T-wave abnormalities and marked QTc prolongation, whereas cardiac biomarkers remained negative. Echocardiography and coronary computed tomography angiography were normal. Fourteen hours later, new concave ST-segment elevation appeared. Cardiac magnetic resonance demonstrated pericardial hyperintensity and enhancement suggestive of inflammatory involvement, without myocardial necrosis. Symptoms resolved after drug discontinuation and colchicine therapy. Discussion: This case illustrates the diagnostic complexity of 5-FU cardiotoxicity, in which vasospastic, electrical, and possible inflammatory manifestations may overlap or evolve sequentially. Take-Home Message: 5-FU cardiotoxicity may present late and exhibit multifaceted manifestations and requires a multidisciplinary approach to balance oncologic efficacy with cardiovascular safety.