Endocrine Abstracts

IgG4 related disease (IgG4-RD) is a rare, multi-organ immune-mediated disorder which manifests as fibro-inflammatory lesions, primarily involving the pancreas, biliary tract, kidneys, lacrimal glands, salivary glands, retroperitoneum, and rarely causing hypophysitis and thyroiditis. We present a 53-yr-old male who was referred with a new diagnosis of diabetes with polyuria, polydipsia, 16 kg weight loss over 3 months, intermittent abdominal pain and diarrhoea. He had a history of coronary artery disease. On examination, acanthosis nigricans and lipodystrophic features were absent. Right axillary and left submandibular lymph node were palpable. He had an HbA1c of 119 mmol/mol, negative islet autoantibodies, abnormal liver function tests [ALT 141 U/l(7-40 U/l); ALP 679 U/l (30-130 U/l)]and low faecal elastase. Viral and autoimmune hepatitis screening was negative. CT scan revealed homogeneous pancreatic enhancement, biliary dilatation, and lymph node involvement. IgG4 levels were elevated [1.73 g/l (range 0-1.30 g/l)}, leading to a new diagnosis of diabetes secondary to hitherto undiagnosed IgG4-related autoimmune pancreatitis (AIP). MRCP indicated focal pancreatitis and severe intrahepatic cholangiopathy. A lymph node biopsy showed reactive follicular hyperplasia. He was treated with prednisolone and insulin therapy. Due to azathioprine intolerance, mycophenolate mofetil was introduced as a steroid-sparing agent. Liver function improved, and subsequent imaging showed significant improvement in cholangiopathy. IGG4-RD can present with pancreatobiliary complications, often misdiagnosed due to symptom overlap with tumors, infections, or immune-mediated diseases. Diagnosing IgG4-related disease (IgG4-RD) as a cause of Type 3c diabetes is challenging but crucial, as corticosteroids and immunosuppressants can lead to radiological, biochemical, and serological improvements. IgG4-RD should be suspected when pancreatitis coexists with salivary or lacrimal gland inflammation, retroperitoneal fibrosis, or renal involvement. Imaging shows a diffusely enlarged pancreas with ductal strictures. Effective management requires a systematic approach, high suspicion, and multidisciplinary team involvement.