# IgG4 disease with multiorgan involvement: a case report

## TL;DR

This paper presents a case of a rare disease affecting multiple organs and emphasizes the importance of accurate diagnosis and treatment.

## Contribution

The case highlights the concurrent involvement of three uncommon sites in IgG4-related disease and its diagnostic challenges.

## Key findings

- The patient showed improvement with oral steroids after diagnosis of IgG4-related disease.
- The case emphasizes the importance of considering IgG4-related disease in differential diagnosis for multiorgan symptoms.
- The paper discusses associations of IgG4-related disease with tuberculosis and lymphomas.

## Abstract

IgG4-related disease (IgG4RD) is a rare fibroinflammatory disease with multiorgan involvement. It presents insidiously over several years and can be a diagnostic enigma. Delays in diagnosis occur due to failure to consider IgG4 as a differential diagnosis, atypical presentations, and an insidious clinical course.

We report the case of a 70-year-old Sri Lankan man with pulmonary, renal, and neurological involvement of IgG4-related disease. Clinical manifestations evolved over a 4-year period and included exertional shortness of breath and dysesthesia of extremities. The diagnosis was established with clinical, radiological, and pathological criteria laid down by The American College of Rheumatology/European League Against Rheumatism in 2019.

Following diagnosis, the patient was started on oral steroids, with rapid improvement of his respiratory and neurological symptoms. He is currently under follow-up and will be monitored with clinical and radiological parameters, complement levels, and lung function tests.

This case outlines the presentation of a patient with IgG4-related disease with concurrent involvement of three uncommon sites. It highlights methods of diagnostic deduction by considering the clinical course of illness, imaging, and histopathology. It also describes evolving associations of IgG4-related disease with tuberculosis and lymphomas, which bear important diagnostic and therapeutic considerations.