Multi-organ IgG4-related disease continues to mislead clinicians: A case report and literature review.

Background: Immunoglobulin G4-related disease (IgG4-RD) is a multisystemic mass forming immune-mediated disease that affects almost every organ and is a diagnostic challenge for every clinician. There is a lack of adequate epidemiological data worldwide, and evidence-based treatment recommendations are not yet established. We report the first case of IgG4-RD from Lithuania and the Baltic Sea region presented with thyroiditis, orbital myositis, orbitopathy, uveitis, scleritis, sialadenitis, autoimmune pancreatitis and prostatitis.

Case Summary: A 54-year-old Caucasian male was admitted to our tertiary Centre complaining of severe weight loss, diarrhoea, abdominal pain, salivary gland swelling, sicca symptoms and diplopia. On examination, bilateral palpable masses in the projection of major salivary glands, severe protrusion of the left eyeball and cachexia were noted. The patient was previously diagnosed with autoimmune thyroiditis and endocrine ophthalmopathy. The magnetic resonance imaging (MRI) of the head revealed enlarged extraocular muscles indicating orbital myositis. The biopsy from the salivary gland mass indicated sialadenitis. Abdominal MRI showed signs of autoimmune pancreatitis, and a serological test revealed the elevated serum IgG4 concentration. The patient was then diagnosed with IgG4-RD and successfully treated with prednisolone. There was a significant clinical, serological and radiological improvement after one month of treatment and no signs of relapse within twenty months. However, it took almost 18 years and the efforts of eight different medical specialists to establish the correct diagnosis.

Conclusion: A comprehensive approach to the patient is essential to improving the recognition of rare immune system conditions, such as IgG4-RD.