Which of the following is an indication for splenectomy in polycythemia vera (PV)?
A. Failure of aspirin to prevent thrombotic complicationsPolycythemia vera (PV) is a clonal, chronic, progressive myeloproliferative disorder characterized by an increase in RBC mass, frequently accompanied by leukocytosis, thrombocytosis, and splenomegaly. Patients affected by PV typically enjoy prolonged survival compared to others affected by hematologic malignancies, but remain at risk for transformation to myelofibrosis or acute myeloid leukemia (AML). The disease is rare, with an annual incidence of 5 to 17 cases per million population. Although the diagnosis may be discovered by routine screening laboratory tests in asymptomatic individuals, affected patients may present with any number of nonspecific complaints, including headache, dizziness, weakness, pruritus, visual disturbances, excessive sweating, joint symptoms, and weight loss. Physical findings include ruddy cyanosis, conjunctival plethora, hepatomegaly, splenomegaly, and hypertension. The diagnosis is established by an elevated RBC mass (>25% of mean predicted value), thrombocytosis, leukocytosis, normal arterial oxygen saturation in the presence of increased RBC mass, splenomegaly, low serum erythropoietin (EPO) stores, and bone marrow hypercellularity. Treatment should be tailored to the risk status of the patient and ranges from phlebotomy and aspirin to chemotherapeutic agents. As in essential thrombocythemia (ET) splenectomy is not helpful in the early stages of disease and is best reserved for late-stage patients in whom myeloid metaplasia has developed and splenomegaly-related symptoms are severe.