IgG4-Related Disease

Expert IgG4-Related Disease diagnosis in Bhopal. Dr. Prateek Deo identifies this rare multi-organ fibro-inflammatory condition with serum IgG4 levels and biopsy.

What is IgG4-Related Disease?

IgG4-Related Disease (IgG4-RD) is a recently recognised, immune-mediated fibro-inflammatory condition that can affect virtually any organ in the body. It is characterised histopathologically by a dense infiltrate of IgG4-positive plasma cells, storiform (cartwheel-pattern) fibrosis, and obliterative phlebitis (destruction of small veins). Elevated serum IgG4 levels are present in approximately 60-70% of affected patients.

IgG4-RD is a "great masquerader" in medicine — its tumour-like presentations in organs like the pancreas, salivary glands, kidneys, and orbits frequently lead to misdiagnosis as malignancy, leading to unnecessary surgery. Recognition of this entity by Rheumatologists has revolutionised management — most patients respond dramatically to corticosteroids, avoiding surgical procedures entirely.

Enlarged pancreas in IgG4-RD

CT scan showing the classic "sausage-like" diffuse pancreatic enlargement of Type 1 Autoimmune Pancreatitis (IgG4-RD).

Organs Affected and Their Presentations

  • Pancreas (Type 1 Autoimmune Pancreatitis): The most common manifestation. Presents with obstructive jaundice, weight loss, and a pancreatic mass — clinically indistinguishable from pancreatic cancer without specialist knowledge.
  • Salivary Glands (Mikulicz's Disease): Bilateral, painless, symmetric enlargement of the submandibular, parotid, and lacrimal glands.
  • Kidneys (IgG4-related tubulointerstitial nephritis): Renal cortical lesions on imaging, rising creatinine from interstitial nephritis.
  • Orbits: Painless orbital swelling causing proptosis (eye protrusion), frequently misdiagnosed as orbital lymphoma or pseudotumour.
  • Bile Ducts (IgG4-related sclerosing cholangitis): Bile duct strictures causing jaundice — mimics primary sclerosing cholangitis or cholangiocarcinoma.
  • Aorta (IgG4-related aortitis): Inflammation and thickening of the aorta wall, potentially causing aneurysm.
  • Thyroid (Riedel's Thyroiditis): Woody-hard thyroid gland with invasion of surrounding structures — the most fibrotic manifestation of IgG4-RD.
Salivary gland biopsy

Biopsy remains the gold standard for confirming IgG4-RD, demonstrating the pathognomonic storiform fibrosis and IgG4+ plasma cell infiltrate.

🔬 Serum IgG4 Limitations

Elevated serum IgG4 levels are not specific for IgG4-RD — they can be elevated in pancreatic cancer, primary sclerosing cholangitis, eosinophilic granulomatosis, and atopic diseases. Conversely, serum IgG4 is normal in 30-40% of biopsy-proven IgG4-RD. Diagnosis must integrate the full clinical, radiological, serological, and histopathological picture — emphasising the need for a specialist Rheumatologist.

Dr. Prateek's Approach to IgG4-Related Disease

IgG4-RD is a condition that requires a physician who is aware of its protean manifestations and can connect the dots across multiple seemingly unrelated organ presentations. Dr. Prateek Deo is skilled in the diagnosis of this recently described condition, saving patients from misdiagnosis as cancer and unnecessary surgery.

Early Recognition

We consider IgG4-RD in any patient with unexplained multi-organ masses, gland enlargement, or obstructive jaundice — preventing unnecessary surgical exploration or oncology referral.

Tissue Biopsy Coordination

When biopsy is indicated, we coordinate with gastroenterologists, urologists, or surgeons to obtain adequate tissue for the specialist IgG4 immunohistochemistry staining required for diagnosis.

Steroid Induction

IgG4-RD typically shows a dramatic, often complete response to Prednisolone — a response that is itself diagnostically informative. We initiate and carefully taper steroid therapy.

Rituximab for Relapse

Relapsing or steroid-dependent IgG4-RD is treated with Rituximab, which targets the B-cells producing pathogenic IgG4 antibodies, providing durable remission.