NIV Congres

Introduction: In patients with obstructive jaundice, the finding of a pancreatic mass or bile duct stenosis, is highly suspicious for a malignancy. However, in some patients, these features can be caused by a benign disease.

Case: A 60-year old patient was admitted with abdominal pain, jaundice and diabetes mellitus de novo. On examination, a mildly jaundiced but otherwise healthy patient was seen. Laboratory investigation revealed cholestatic liver function tests. Computer-Tomography of the abdomen showed a diffuse enlarged pancreas. Additionally, another mass at the distal aorta was detected. An ERCP visualized a stenosis of the common bile duct and intrahepatic bile duct. A stent was placed and laboratory results rapidly improved. Brush cytology only showed reactive cells. A biopsy of the pancreas via endo-ultrasonography showed no representive tissue. As the patient remained in good condition without alarming symptoms, it was hard to believe a malignancy was present. As the unexplained mass around the aorta was not compatible with a pancreatic- or cholangiocarcinoma, a retroperitoneal fibrosis as a component of an immunoglobin G4 (IgG4)-related inflammatory disease with associated autoimmune pancreatitis and autoimmune cholangitis was considered. Indeed, the plasma IgG4 level in this patient was elevated (2.7 g/l, n = 0.08-1.4). Prednisolon 60 mg per day was started. After several weeks his need for insulin decreased, liver function improved and prednisolon was tapered. The ERCP showed remarkable normal bile ducts after stent removal.

Discussion: IgG4 related inflammatory disease is a recent new recognized group of diseases, that can mimic a pancreatic malignancy or cholangiocarcinoma. Often diagnostic imaging cannot differentiate between malignancy and IgG4 related disease. If there is a paradox between the good condition of the patient and the suspicion of a malignancy, one should search for other IgG4-associated diseases. Retroperitoneal fibrosis, (peri)aortitis, autoimmune pancreatitis, sclerosing cholangitis, sialadenitis or tubulointerstitial nephritis are the most common in this collection of disorders. Typically, IgG4 levels are elevated in 60 to 70 percent of the patients. Histological findings of dense infiltration of IgG4 positive lymphocytes with fibrosis can confirm the diagnosis. Clinicians must be aware of this new entity as the prognosis is very different and patients respond well to steroid therapy. Also, unnecessary surgery can be prevented if the diagnosis is made correctly.