Inflammatory pseudotumor.

Inflammatory pseudotumor is a quasineoplastic lesion that most commonly involves the lung and the orbit, but it has been reported to occur in nearly every site in the body. The pathogenesis, natural history, clinical presentation, imaging findings, and treatment options for inflammatory pseudotumor in the lung, heart, gastrointestinal tract, adrenal gland, iliopsoas muscle, orbit, and central nervous system are discussed. Because inflammatory pseudotumors mimic malignant tumors both clinically and radiologically, the radiologist should be familiar with this entity and help avoid unnecessary radical surgery when possible.