Budd-Chiari syndrome due to polycythemia vera with JAK2 mutation: A case report on the application of Transjugular Intrahepatic Portosystemic Shunt (TIPS).

Introduction We present the first reported case in Latin America of the association of Budd-Chiari Syndrome (SBC) with Polycythemia Vera (PV) in a pediatric patient who had a clinically indolent course. At the time of diagnosis, the patient had already developed complications of advanced liver disease, necessitating a portosystemic shunt as a rescue treatment. The procedure was performed successfully, with positive outcomes during follow-up. Polycythemia Vera (PV) is a part of Philadelphia-negative myeloproliferative neoplasms, characterized by clonal erythrocytosis with normal morphology and leukocytosis. Clinical manifestations include splenomegaly, thrombosis, bleeding, and, in the long term, potential transformation to myelofibrosis or leukemia. The reported incidence varies between 0.5-4 cases per 100,000 person-years. Diagnostic criteria for PV include hematocrit >52% in men, >48% in women, or an increase in red blood cell mass >25% above predicted values, along with a mutation in the JAK2 gene (requiring both criteria). About 96% of PV patients have a JAK2 gene mutation, with 3% presenting somatic activating mutations in exons 14 (JAK2V617F) and 12 of JAK2, respectively. Calreticulin mutations (CALR: 19p13.2) are rare in PV.