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Gastrointestinal Imaging

E3149. Imaging Spectrum of IgG4-Related Disease

Litt B,  Islam O. Queen’s University, Kingston, Canada

Address correspondence to B. Litt (brendan.litt@gmail.com)

Background Information: IgG4-related disease is a rare disease increasingly recognized as a multiorgan process. It can manifest in virtually any organ system. It was first identified in the setting of autoimmune pancreatitis. Many conditions once accepted as orphan diseases have been recategorized into the spectrum of IgG4-related disease, with cases identified in the brain, meninges, orbits, salivary glands, thyroid, heart, mediastinum, solid organs of the abdomen and pelvis, and retroperitoneum. This exhibit will review key imaging and pathologic findings that raise suspicion of this entity.

Educational Goals/Teaching Points: Following this presentation, the learner will recognize the spectrum of CT and MR findings in IgG4-related disease. The learner will appreciate the possible organs of involvement, and know when to question the possibility of this disease process.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques: The reference standard of diagnosis in this disease is histopathology. Three key pathologic features are lymphoplasmacytic infiltration, obliterative phlebitis, and storiform fibrosis. These are outlined in the presentation. The exhibit provides a review of key imaging findings in cases of suspected and pathologically proven IgG4-related disease. From a radiologic perspective, the involvement of IgG4-related disease is oftentimes nonspecific. Slides outline pitfalls in making the diagnoses, including an instance of IgG4-related pancreatitis misdiagnosed as pancreatic neoplasm. Additional cases include hypertrophic pachymeningitis, retroperitoneal fibrosis, orbital pseudotumor, and retroperitoneal fibrosis.

Conclusion: IgG4-related disease is a newly accepted but poorly understood clinical entity requiring increased familiarity in the medical community. Ultimately, the possibility should be raised in the setting of fibrosclerosing disease on imaging. Radiologists play a vital role in the initial diagnosis of this challenging disease. IgG4-related disease is generally treatable, with a favorable response to corticosteroid therapy. By providing a timely diagnosis, the radiologist can ensure that patients receive appropriate referral, counselling, and treatment.