The emergence of targetable MEKanisms in sporadic lymphatic disorders.

Sporadic lymphatic diseases are orphans among orphans in the medical community, a diverse collection of disorders at the intersection of cardiac, gastrointestinal, pulmonary, dermatologic, and oncologic disease that receives only passing attention in medical school and that no subspecialty in medicine fully embraces as its own. They often present in a confusing and illusive manner, with a fractured bone, expectoration of blood or a branching airway cast, a swollen limb or a collection of chylous material; protean manifestations that can challenge even the most expert diagnostician. Yet many of these acquired disorders have been discovered to have a targetable genetic basis, and as the case report of Foster et al (2020) demonstrates, the sedulous clinician-patient dyad can be rewarded with an almost miraculous result when the molecular pathogenesis of the disease is pursued and an exquisitely targeted therapy is administered.