A 62-year-old man who had diffuse discomfort in middle upper abdomen, accompanied by brown urine. Blood test showed abnormal liver function, with IgG4 4.830g/L↑. Ultrasound gastroscopy showed uneven internal high-low echo and poor internal blood signal in pancreatic neck lesion, (size about 2.0×2.5 cm2) with clear boundary. The lesion was located adjacent to the portal vein and superior mesenteric vein. No obvious expansion of the main pancreatic duct in the body and tail pancreas was found. Possible malignancy was considered.
MRCP (Magnetic Resonance Cholangiopancreatography) showed that the intrahepatic bile duct was slightly dilated, common bile duct was dilated, inflammation of lower segment of common bile duct was possible, and the malignancy could not be excluded.
Thin-slice enhanced CT scan of pancreas showed the uncinate process of pancreatic head lesion, suggesting possible malignancy with intrahepatic and extrahepatic bile duct dilatation.
In order to identify the nature of pancreatic lesions, further PET/CT scanning was performed. 18F-FDG PET/CT showed the uncinate process of pancreas was mildly enlarged with bile duct tree dilated, the FDG metabolism was slightly increased in uncinate process and head of pancreas (SUVmax=4.07, SUVmean=2.25, 2.4cm*1.8cm), the possibility of malignant tumor was considered. (Fig. A–D).
After two weeks of symptomatic treatment, the liver function improved significantly. However, as the above modalities could not exclude the possibility of pancreatic malignancy, 68Ga -FAPI PET/MR scanning was recommended.
According to the PET/MR scan (Fig. E–H), 68Ga-FAPI uptake was evenly elevated in the entire pancreas (SUVmax=11.04, SUVmean=6.15). Increased 68Ga-FAPI uptake was also found around dilated intrahepatic and extrahepatic bile duct (SUVmax=3.61, SUVmean=1.92). PET/MR diagnosed unequivocally IgG4-RD that involved pancreas and intrahepatic and extrahepatic bile duct.