Presentation
Epigastric pain. Evaluate the gallbladder.
Patient Data
The gallbladder cannot be visualized. A large (20.6 x 11.8 cm) heterogeneous mass with a lobulated border lies beneath the liver, compressing the right kidney. The mass shows internal flow and central stellate necrosis. Splenomegaly is also noted.
Large solid heterogeneous mass with a necrotic center in the right upper abdomen, exerting mass effect on the IVC, liver, porta hepatis, pancreas, and right kidney. The mass is most likely extrahepatic-retroperitoneal, although an intraperitoneal component cannot be confidently ruled out. The mass undergoes heterogeneous enhancement. The solid component at its posteroinferior aspect engulfs the renal accessory vessel. Retroperitoneal-perirenal fat edema is present.
The liver is of normal size and contour. Its medial aspect and porta hepatis are compressed by the mass. Diffuse hepatic fatty infiltration. Heterogeneous hepatic enhancement at the arterial phase, most probably due to mass effect on the hepatic vessels. No focal intrahepatic mass.
The gallbladder contains numerous tiny calculi.
The spleen is enlarged, 16.4 cm in the craniocaudal plane.
Small simple cortical cysts in both kidneys.
Status post bariatric surgery. The duodenum is displaced by the mass and there is no separation plane between them.
No enlarged intra-abdominal lymph nodes.
Venous collaterals coursing in the abdominal wall.
Conclusion
Solid, partially necrotic, right upper abdominal mass displacing adjacent organs. Impression of disrupted venous drainage due to compression of the IVC. The mass is most probably extrahepatic-retroperitoneal; an intraperitoneal component cannot be ruled out.
Differential diagnosis includes a duodenal GIST, retroperitoneal sarcoma, or other solid fibrous/mesenchymal tumor.
Case Discussion
A young, previously healthy man complained of epigastric pain for a couple of weeks which started radiating to his back. History of bariatric surgery several years earlier.
The abdominal x-rays (not shown) were interpreted as normal.
Abdominal ultrasound revealed a large mass beneath the liver. It was difficult to determine whether the mass protruded from the liver, from another organ, or was a standalone retroperitoneal mass.
MRI liver demonstrated sharp angles between the mass and the liver. Since there was no visual separation plane between the mass and the duodenum, a duodenal GIST was included in the list of differentials.
Failed attempt of EUS due to compression of the duodenal bulb by the mass.
PET-CT performed three days after the MRI (not shown) demonstrated a large right upper quadrant mass displacing adjacent organs and possibly partially occluding the IVC. Strong radiotracer uptake in the mass with central necrosis and less avid uptake in two nearby masses.
The patient went on to have a percutaneous biopsy.
Histology
Undifferentiated pleomorphic sarcoma. Ki67 = 30%. DOG1 negative.
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