Presentation
This patient presented to the ED following a road traffic accident. Because of right upper quadrant pain a CT abdomen was performed.
Patient Data
There is a 7.5 x 6.2 x 6.7 cm hyperenhancing mass adjacent to the inferolateral wall of the second and third parts of the duodenum with patchy hypodense regions, likely representing areas of necrosis. A feeding vessel appears to arise from the inferior mesenteric artery. Multiple large (15 mm diameter ) serpiginous vessels extend from the inferior margin of the mass and appear to represent veins draining into the IVC, with commensurate elevation of density of blood in the IVC before and after the mass. No surrounding desmoplastic reaction.
Hypodensity in the liver adjacent to the ligamentum teres in keeping with focal fatty infiltration.
The gallbladder, spleen, pancreas, kidneys and adrenals are unremarkable. No lymphadenopathy by size criteria.
Soft tissue stranding over the abdomen in a seatbelt distribution without any large hematoma.
No free intraperitoneal gas or fluid. The lung bases are clear. No destructive osseous lesion.
Conclusion: 7.5 cm mass adjacent to the duodenum with large draining veins. The differential includes a sarcoma, and given the prominant vascular component perhaps and angiosarcoma, or GIST (D2/3 junction). No evidence of metastatic disease.
Reference is made to the trauma CT examination. A 7.8 cm x 6.3 cm x 6.3 cm rounded mass is again identified located in the right side of the abdomen, closely associated with segments V3 at the duodenum and retroperitoneal in location. The mass is also immediately adjacent to the pancreatic head from which it is felt to be separate. There is mass-effect with compression of the inferior vena cava. The mass itself appears encapsulated. It is heterogeneously T2 vividly hyperintense and T1 hypointense. No fat content. The lesion vividly and heterogeneously enhances with relatively rapid washout. Prominent intralesional flow voids and large draining veins are seen immediately inferior to the mass. The vasculature returns to the IVC.
Other structures are abutted by the mass are the non-dilated right ureter, right psoas major muscle, distal aorta and right colon all of which appear unremarkable.
There is no duodenal or gastric outlet obstruction.
No lymphadenopathy
Pancreas is normal in appearance with no focal pancreatic lesion identified. The main pancreatic duct is non-dilated. No peripancreatic fluid collection.
The biliary tree is normal in caliber and appearance. There is no evidence of gallstone disease. The gallbladder is unremarkable.
Within segment 2 of the liver, there is a statically T2 hyperintense lesion measuring 1.9 centimeters. This is not visible on T1 weighted imaging. There is arterial hyper enhancement ( but not nearly as avidly as the abdominal mass ) without washout, and persistent mild hyper enhancement on later phases.
Conclusion:
7.8cm retroperitoneal tumor adjacent to the third part of the duodenum and IVC, but felt to be separate from pancreas. The most likely diagnosis is of a paraganglioma, with the main differential being a gastrointestinal stromal tumor (do not typically enhance so vividly). Other forms of sarcoma remain in the differential. Clinical markers and nuclear scan exclusion of a phaeo/paraganglioma strongly suggested before biopsy (via EUS) is contemplated.1.9 cm segment 2 liver lesion is ill-defined. Correlation with contrast enhanced US suggested to confirm this is a real lesion and if so, possible nature.
Right retroperitoneal mass demonstrates avid radiotracer uptake. No other sites of disease seen.
Findings are in keeping with a neuroendocrine tumor.
Biochemsitry
MACROSCOPIC DESCRIPTION: "Paraganglioma": A portion of soft yellow-tan tissue 90x85x60mm. Entirely inked blue. Sectioning reveals a homogeneous pale tan tumor surrounded by a thin fibrous capsule.
MICROSCOPIC DESCRIPTION: Sections show a thinly encapsulated tumor composed of nests and trabeculae of polygonal cells in a stroma with prominent small vessels. The cells have round to oval nuclei, fine chromatin, inconspicuous nucleoli and a moderate amount of vacuolated eosinophilic cytoplasm. Scattered bizarre cells are noted. Mitoses are not a feature. No necrosis is seen. By immunohistochemistry the tumor cells are CD56, synaptophysin and chromogranin positive. Staining for S100 highlights sustentacular cells.
DIAGNOSIS: Lesion, site unstated: Paraganglioma.
Case Discussion
Images of gross pathological specimen and histology, and macro- and microscopic descriptions kindly provided by Dr Mohammed Swayyed (Registrar in Pathology, The Royal Melbourne Hospital).
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