Cardiofaciocutaneous syndrome with KRAS gene mutation presenting as chylopericardium

A 12-year-old female patient with cardiofaciocutaneous syndrome in the presence of a KRAS gene mutation had episodes of pericardial effusion on ultrasound, later confirmed to be chylopericardium, which resolved after a lymphangiography. We discussed herein the pathophysiological background of this rare case and the efficacy of lymphangiography in the treatment of chylopericardium.