# Immunoglobulin G4 disease-related retroperitoneal fibrosis: A series of five cases

## TL;DR

This case series explores the imaging features of IgG4-related disease affecting retroperitoneal organs, aiding in distinguishing it from retroperitoneal fibrosis.

## Contribution

The study presents five cases highlighting the imaging appearances of IgG4-related retroperitoneal fibrosis.

## Key findings

- Multidetector CT scans are useful for diagnosing IgG4-related disease involving retroperitoneal organs.
- Imaging findings include localized masses or organ enlargement in affected areas.
- The study helps differentiate IgG4-related disease from retroperitoneal fibrosis using radiological features.

## Abstract

Immunoglobulin G4 (IgG4)-related disease has the potential to impact any part of the body, including the walls of large- and medium-sized blood vessels and the ureters. While histopathologic examination is currently the standard method for identifying organ involvement and diagnosing IgG4-related disease (IgG4-RD), obtaining biopsy or surgical samples from vessel or ureteral walls is challenging. Given that patients may display only mild symptoms, non-invasive imaging plays a vital role in both diagnosing and managing IgG4-related diseases. Multidetector CT scans are valuable in establishing the primary diagnosis, identifying anatomical landmarks and assessing their relationships. Involvement of the genitourinary organs, such as the ureter, bladder, urethra, and male and female reproductive organs in IgG4-RD, is infrequent when compared to kidney involvement. The imaging findings may include the presence of a localised mass within or surrounding the affected organ or a generalised enlargement of the organ. This report includes cross-sectional images of five cases of IgG4-RD involving large- and medium-sized blood vessels (the aorta and superior mesenteric artery) and the ureters.

This case series provides insight into the various imaging appearances of IgG4-related retroperitoneal organ involvement and helps differentiate it radiologically from retroperitoneal fibrosis.