Hematoma de músculo iliopsoas na vigência de tratamento com varfarina

warfarin is a widely used drug for the prevention of thromboembolic events. knowledge of its adverse effects is necessary for patient follow-up. although the development of blood dyscrasias is a potential complication in these patients, retroperitoneal bleeding is rare. this article reports the case of a patient who developed iliopsoas muscle hematoma during treatment with warfarin after implantation of a metallic prosthetic aortic valve. the clinical manifestations involved important differential diagnoses.