Retroperitoneal fibrosis

This code represents retroperitoneal fibrosis, a rare disorder characterized by the proliferation of fibrous tissue in the retroperitoneum. This fibrotic process can encase and obstruct retroperitoneal structures, most commonly the ureters, leading to hydronephrosis and renal impairment.

Use this code when documentation clearly indicates a diagnosis of retroperitoneal fibrosis, whether idiopathic or secondary to other conditions. Supporting documentation should detail the presence of retroperitoneal fibrotic tissue, often identified through imaging studies like CT or MRI.

• Differentiate between idiopathic retroperitoneal fibrosis and secondary forms; if secondary, code the underlying cause first.
• Be sure to also code any associated complications, such as hydronephrosis (N13.30-N13.39) or renal failure.
• Review documentation for laterality if the fibrosis predominantly affects one side, although retroperitoneal fibrosis is often diffuse.