RESUMEN
Priapism is a painful medical condition in which the erect penis does not return to its flaccid state, despite the absence of both physical and psychological stimulation, within 4 h. Priapism is considered a medical emergency, which should receive proper treatment by a qualified medical practitioner. Treatment initially involves conservative measures, such as corporeal aspiration and irrigation with saline or dilute phenylephrine. If this fails, embolization or surgical shunting may be required. Priapism is more commonly associated with sickle cell hemoglobinopathy. However, hyperviscosity resulting from leukemia is a rare cause of priapism. We report a case of a 19-year-old man with an 18-h history of priapism secondary to undiagnosed chronic myeloid leukemia. We discuss the method of leukapheresis (mechanical white cell depletion) to reduce viscosity.