Case 4
A 77-year-old male with known retroperitoneal fibrosis resulting in bilateral ureteric strictures (status post DJ stenting) was admitted for replacement of bilateral DJ stents. PET-CT was performed during the hospital stay to rule out neoplastic disease. PET-CT showed an interval hypermetabolic hypodense lesion in the head of pancreas. Besides that, there was redemonstration of soft tissue retroperitoneal fibrotic mass encasing the lower abdominal aorta with mild FDG avidity without interval change. CT abdomen and pelvis with contrast reported focal hypodense area at the junction of the pancreatic head and neck of corresponding to the hypermetabolic area identified on PET/CT (Figure 5 ). Findings were reported as neoplastic disease. His serum CA19-9 (non-detectable to 39 U/mL) and CEA (0-3.0 ng/mL healthy subjects) were 304 and 4.27 respectively. At follow up visit after one month his serum IgG-4 level was also requested which was measuring 11100 mg/L. Based on the imaging features and IgG-4 levels diagnosis of IgG-4 disease was made. The patient was started on oral steroids. Serum IgG-4 level repeated after two months was measuring 5440 mg/L. Follow up CT did not show any focal lesion in the pancreas.