Intimal angiosarcoma masquerading as retroperitoneal fibrosis.

We present a rare case of intimal angiosarcoma arising from the iliac artery with unusual symptoms and signs mimicking retroperitoneal fibrosis (RPF). This 84-year-old male presented with constitutional symptoms, abdominal pain, increased acute-phase reactant levels, impaired renal function and a CT-documented left-sided parailiac soft-tissue mass with unilateral extrinsic ureteric obstruction. Whole-body F-fluorodeoxyglucose positron emission tomography scan showed highly increased FDG-uptake in a horseshoe-like pattern surrounding the left common iliac artery, but no pathologic activity elsewhere.