Presentation
History of pancreatitis, presenting with non-specific abdominal pain. Incidental finding of free fluid in pelvic recesses during ultrasound. CT is performed.
Patient Data
Axial contrast-enhanced CT in portal venous phase: retroperitoneal mass with infiltrative and spiculated appearance. Renal vein, renal arteries and inferior cava vein are stenosed. Portosystemic collateral pathways in the hypogastrium are noted. Ureter retraction and mild left hydronephrosis are also present.
Multiple round shaped cortical nodules, nonexpansive and hypovascular in this phase.
Hypodense lesion in the spleen of fluid density, confirmed to be a simple cyst by ultrasound.
Restricted diffusion in renal lesions with low ADC values and high DWI.
Progressive and delayed contrast enhancement of the retroperitoneal mass suggestive of fibrotic tissue.
Follow up CT one year after:
Intrahepatic biliary tree dilatation with focal thickening of the bile duct walls, which also demonstrate enhancement.
Also of note is an enlarged pancreatic tail with loss of the lobular contour, absence of pancreatic clefts and mild fat stranding.
Significant improvement of the previously discussed radiological findings after treatment. The patient is still on medication and remains asymptomatic.
Case Discussion
Patient had a history of acute pancreatitis 10 years before. No underlying cause was found at the time (no history of alcohol abuse, no gallstones found on ultrasound).
In this case, IgG4-related disease is the primary concern considering both the retroperitoneal mass and the bilateral renal lesions. The fact that the renal lesions demonstrate restricted diffusion is also a typical feature of IgG4's deposits.
IgG4 levels were high on laboratory tests.
The differential diagnosis of the retroperitoneal mass would be idiopathic retroperitoneal fibrosis, lymphoma and malignant retroperitoneal fibrosis, with a differential diagnosis of pyelonephritis or metastases for the renal lesions.
Probably we can consider that the first episode of pancreatitis was also a manifestation of the IgG4-related sclerosing disease. The patient was treated with corticosteroid therapy, resulting in a reduction in the volume of the retroperitoneal mass. During follow up he developed autoimmune pancreatitis and IgG4-related sclerosing cholangitis, and was treated consequently with significant improvement of the findings.
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