IgG4-related double duct sign mimicking pancreatic head cancer
QJM: Quarterly journal of medicine
A 58-year-old man presented with a 1-month history of teacolored urine and pruritus. Physical examination revealed yellowish discoloration of skin and sclera without abdominal tenderness. Laboratory investigations showed as following: aspartate aminotransferase of 28 U/l (normal range, 32), alanine aminotransferase of 24 U/l (31), c-glutamyl transferase of 48 U/ l (35), alkaline phosphatase of 124 U/l (100), total bilirubin of 18.8 mg/dl (1.0), direct bilirubin of 13.5 mg/dl (0.2) and lipase
... (0.2) and lipase level of 224 U/l (82). Magnetic resonance cholangiopancreatography demonstrated stricture of the distal common bile duct (CBD) and dilatation of the pancreatic duct (PD). Endoscopic retrograde cholangiopancreatography (ERCP) showed gradually tapering appearance of the CBD (Figure 1 , arrow) and PD (Figure 1 , arrowhead) with double duct sign. Following laboratory tests revealed as following: carcinoembryonic antigen of 1.17 ng/ml (5.0), cancer antigen 19-9 of 3.6 U/ml (37) and Immunoglobulin G4 (IgG4) level of 2583.0 mg/dl (86.4). After 8-week of steroid treatment, the levels of hepatobiliary enzymes and IgG4 were back to normal limits. Repeated ERCP showed nearly normal appearance of the CBD and PD. IgG4-related disease had been well documented to involve many organs, such as lymph nodes, pancreas, salivary gland, thyroid gland, biliary tract, retroperitoneum, kidney, gallbladder, mesentery, lung and prostate. IgG4-related pancreatitis is the most common manifestation of IgG4-related diseases. However, IgG4-related diseases always involve multiple organs simultaneously. The characteristics and image findings of IgG4related diseases depend on the involved organs. 1 Like our patient, the presentations of IgG4-related pancreatitis and cholangitis could mimic cholangiocarcinoma. IgG4-related pancreatitis can be divided into three types, including diffuse, focal and multifocal. Diffuse type is the most common type of autoimmune pancreatitis, which represent a diffuse enlarged sausagelike pancreas. Focal type is less common and could manifest as a focal mass, which always involve the pancreatic head and the presentations can lead to a misdiagnosis as pancreatic malignancy. IgG4-related cholangitis often coexist with pancreatitis. The involved segments of biliary tract present focal thickening, irregularity and stenosis, which can result in upstream biliary dilatation and obstructive jaundice. 2 In clinical practice, a high index of suspicion is always necessary for diagnosis of IgG4related diseases. In addition to the clinical history of patients, the diagnosis of IgG-4 related diseases is based on elevated serum IgG4 level, or the diagnostic histological findings, which show infiltration of T lymphocyte and IgG4-positive plasma cell in the target organs. Treatment with corticosteroids could be effective and surgery should be unnecessary. 3 Photographs and text from: C.-T.