Acute Promyelocytic Leukemia Accompanied with Venous Thrombosis Subsequent to Upadacitinib Therapy

Upadacitinib is an oral selective Janus kinase 1 (JAK1) inhibitor that targets specific pathways in immune-inflammatory responses. It is increasingly being utilized in the treatment of certain autoimmune diseases. There have been reports of solid tumors and thromboembolic events associated with upadacitinib use. However, to date, no reports have linked upadacitinib therapy to leukemia. Here, we present the first documented case of acute promyelocytic leukemia (APL) complicated by lower extremity venous thrombosis following upadacitinib treatment for vitiligo. The patient maintained normal or mildly reduced platelet counts throughout the clinical course, with no significant coagulation abnormalities requiring component blood transfusions. The patient achieved complete remission following standard induction therapy with all-trans retinoic acid and arsenic trioxide, with an uneventful treatment course. Notably, this clinical presentation markedly differs from typical APL cases, demonstrating unique biological characteristics.