Rapid Hepatomegaly From Ruxolitinib Discontinuation Syndrome.

Introduction: Ruxolitinib (RUX) is a Food and Drug Administration-approved Janus Kinase (JAK) inhibitor shown to be effective in improving hypercatabolic symptoms and splenomegaly in patients with myelofibrosis (MF). RUX therapy provides symptomatic benefits for MF patients but is often discontinued for various reasons including worsening cytopenias. Ruxolitinib Discontinuation Syndrome (RDS) involves an acute cytokine-storm rebound phenomenon that can manifest as an acute relapse of symptoms, worsening splenomegaly, respiratory distress, systemic inflammatory response syndrome, or disseminated intravascular coagulopathy.