When Essential Thrombocythemia Goes Triple-Negative: A Case of Acquired von Willebrand Disease.

Essential thrombocythemia (ET) is a type of myeloproliferative neoplasm (MPN) disorder characterized by persistent thrombocytosis and characterized by frequent association with cellular genetic alterations. The 10%-15% of ET that is not associated with genetic abnormalities is known as triple-negative essential thrombocythemia (TNET). A common complication observed in around 20% of ET patients is the development of acquired von Willebrand disease (AvWD). Acquired von Willebrand disease affects 10-20% of myeloproliferative neoplasm cases, often linked to essential thrombocythemia with extreme thrombocytosis, but its incidence in triple-negative ET is undiscovered. We present the case of a 43-year-old male who was referred to our clinic with a platelet count of 844 x 103/µL and a workup including bone marrow aspirate and pertinent labs revealing TNET. A four-year history of platelet counts was available, revealing a gradually progressive trend upward. Acquired von Willebrand disease appeared approximately one month before his platelet count peaked at 1,200 x 103/µL, and hydroxyurea and aspirin were started. The platelets gradually decreased and stabilized by six months around 400 x 103/µL. The complexities of this case lie in the dual management of thrombocytosis-related thrombotic risks and AvWD-associated bleeding tendencies, exacerbated by the absence of standardized treatment guidelines tailored specifically to this patient subgroup. In this case, TNET and AvWD patients with a four-year survey of platelet counts demonstrated a good response to oral aspirin and oral hydrea daily.