Retroperitoneal Fibrosis as a Cause of Chylous Ascites

Retroperitoneal fibrosis is a rare condition characterized by chronic inflammation and marked fibrosis of the retroperitoneal tissue, often leading to entrapment of abdominal organs. We report a 69-year-old white man who presented with a 5-week history of gradual onset of progressive abdominal distension. He had no history or risk factors for an underlying liver condition. Ascites and a retroperitoneal mass encasing the major abdominal vessels were revealed on imaging. Biopsies of the mass confirmed the presence of retroperitoneal fibrosis, and the ascitic fluid was milky, consistent with chylous ascites. We discuss this rare presentation and the challenges of treatment for chylous ascites caused by RPF, including the role for supportive treatment.