Features and Prognosis of Patients With Retroperitoneal Fibrosis Developing Fibrosing Mediastinitis: Case-Control Study and Systematic Review.

Objective: Retroperitoneal fibrosis (RPF) complicated by mediastinal fibrosis (MF) is rare but fatal. We aimed to explore the features and indicators of poor prognosis for the population of those affected.

Methods: Patients with idiopathic RPF were recruited in Peking University International Hospital. Literature related to RPF with MF was searched from PubMed, Web of Science, and Embase until September 2024. Systematic review and case-control studies were conducted.

Results: One patient with RPF and MF from our center and nine cases identified through literature search formed the study group. The remaining 51 patients with RPF who did not have MF were enrolled as the control group. Patients with RPF and MF were more likely to present specific symptoms, including emaciation (30% vs 2%), fever (20% vs 0), pericardial effusion (30% vs 0), pleurisy (20% vs 0) and dyspnea (40% vs 0) (all P < 0.05). Hyperglobulinemia (elevated IgG levels) was also more predominant in the study group, whereas low back pain (20% vs 56.9%, P = 0.043) was less prevalent. Four of 10 patients in the study group died, but none died in the control group. A second case-control study was performed among patients with RPF and MF, with the three patients who died of fibrosis disease as the study group and the surviving six patients as the control group. It was found that pleural effusions (100% versus 16.7%, P = 0.048) and the absence of glucocorticoid treatment were risk factors for death in patients with RPF and MF.

Conclusion: RPF with MF has specific clinical features and poor prognosis. Early detection and glucocorticoids-based treatment could improve the outcome.