Based on the imaging findings and clinical presentation, can you formulate a relative diagnosis?
The presence of a retroperitoneal fibrotic mass, which is not elevating the aorta, a bulky pancreatic head, and evidence of biliary obstruction, all together with elevated IgG-4 serum levels, favor a diagnosis of an IgG-4 related disease. (Retroperitoneal fibrosis with associated mass-forming autoimmune pancreatitis and sclerosing cholangitis).
List the two types of retroperitoneal fibrosis.
Idiopathic (IgG-4 related disease) and Secondary (drugs, trauma, surgery, radiotherapy, infections (TB), malignancy)
True or False: In retroperitoneal fibrosis, the aorta and IVC are elevated anteriorly from the spine.
False. The presence of anterior displacement of the abdominal aorta and inferior vena cave may help distinguish between benign retroperitoneal fibrosis from an underlying malignancy in the retropritoneum. In retroperitoneal fibrosis, it is unusual to see an elevated aorta or IVC. In contrast to benign retroperitoneal fibrosis, malignant processes arising from the retroperitoneal area tend to elevate the abdominal aorta and IVC anteriorly from the spine due to enlarged retroperitoneal lymph nodes lying posterior to these major vessels.
The pancreas appears bulky, specifically the pancreatic head and uncinate process, surrounded by minimal peripancreatic fat stranding. Multiple enlarged peripancreatic lymph nodes can be appreciated in the suprapancreatic and pancreaticoduodenal stations.
The common bile duct appears dilated, with evidence of distal common bile duct wall thickening, and associated intrahepatic biliary tree dilatation, more marked in the left lobe of the liver.
The liver, however, is of normal size and contour, with no focal liver lesions.
The abdominal aorta appears diffusely diseased, with multiple atherosclerotic plaques. A low attenuation, circumferential periaortic mass is seen surrounding the abdominal aorta, superior mesenteric artery, right colic artery and inferior mesenteric artery, and extends down to involve both common iliac and internal iliac arteries. This mass appears isodense to the abdominal aorta and IVC in the delayed phase, in keeping with delayed enhancement, likely relating to advanced disease. No significant anterior displacement of the abdominal aorta or the IVC is seen.
Both ureters appear to be embedded within the retroperitoneal fibrotic mass, with medial deviation and abrupt tapering at the level of L4 vertebral body. Mild bilateral hydronephrosis is evident.
No focal lytic or sclerotic lesions are seen in the imaged portions of the spine or the bony pelvis.