Kaposiform lymphangiomatosis effectively treated withMEKinhibition

Kaposiform lymphangiomatosis (KLA) is a rare lymphatic anomaly primarily affecting the mediastinum with high mortality rate. We present a patient withKLAand significant disease burden harboring a somatic point mutation in theCasitas B lineage lymphoma(CBL) gene. She was treated withMEKinhibition with complete resolution of symptoms, near-complete resolution of lymphatic fluid burden, and remodeling of her lymphatic system. While patients withKLAhave been reported to harbor mutations inNRAS, here we report for the first time a causative mutation in theCBLgene in a patient withKLA, successfully treated with Ras pathway inhibition.