RESUMEN
BACKGROUND: Juvenile Dermatomyositis (JDM) is a rare disorder with subtypes associated with different myositis-specific antibodies (MSAs) including anti-MDA5. Hepatic involvement in JDM is rare and has not previously been documented in anti-MDA5 JDM. There is a lack of formal research on treatment protocols for anti-MDA5 JDM, though tofacitinib is a highly regarded emerging therapy. CASE PRESENTATION: A previously healthy 14-month-old Hispanic female presented to a pediatric rheumatology clinic with eight months of worsening rash, weakness, periorbital edema, intermittent fevers, and weight loss. Her physical exam was notable for fever, thinning of hair, heliotrope rash, periorbital edema, violaceous macules on her bilateral elbows, forearms, arms, and knees, arthritis, Gottron's sign, and hepatomegaly. The patient was admitted, and symptoms progressed to include hypoxemia. Subsequent workup was notable for ground glass opacities of bilateral lung fields on chest CT, myositis visualized on MRI and confirmed with muscle biopsy, and liver biopsy showing nonspecific signs of liver injury. After a thorough infectious disease workup to rule out concomitant infection, the patient was started on high-dose steroids and induction with cyclophosphamide. She responded well with disease remission maintained with tofacitinib in the outpatient setting. DISCUSSION AND CONCLUSIONS: Our patient is notable due to her young age at presentation, histopathologically confirmed liver injury, and response to treatment. The case adds to the growing body of literature supporting tofacitinib for anti-MDA5 JDM in the pediatric population. Future research can better standardize effective treatment protocols and define the mechanism of liver involvement. For patients with nonspecific liver injury, muscular, and cutaneous disease, anti-MDA5 JDM should be considered in the differential diagnosis with treatment options including tofacitinib for confirmed cases.