Idiopathic retroperitoneal fibrosis (IRF) is a rare condition in which a mass of fibrous tissue encompasses the abdominal aorta and the common iliac arteries. Although the histologic findings of IRF are mostly benign, its diagnosis is often delayed, leading to significant physiologic deteriorations, namely renal insufficiency, and poor treatment prognosis. Back pain, which is a common presenting symptom, may lead to confusion in determining the diagnosis of IRF. This report presents a patient with retroperitoneal fibrosis whose diagnosis was delayed due to the concomitant presence of myofascial pain syndrome and lumbar intervertebral disc herniation. (J Korean Acad Rehab Med 2009; 33: 123-126)
