A giant liposarcoma originating from peripancreatic fat tissue with identification using 3D-CT angiography: a case report

Figures

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  Fig. 1. Abdominal CT and MRI. A, B Abdominal contrast-enhanced CT. C Abdominal plain MRI T2-weighted image. D Abdominal plain MRI fat-suppressed T2-weighted image. A giant tumor measuring 34 cm predominantly composed of fat tissue was observed in the abdomen (white triangles). A high density area of the ventral side of the tumor was detected on CT (white arrows), and the region showed equivalent-signal intensity area to renal parenchyma on MRI T2-weighted image and not suppressed on fat-suppressed images (white arrows)

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  Fig. 2. 3D-CT angiography. A Coronal image, B Sagittal image, C Schema. The tumor’s feeding artery was identified as a branch of the DPA. CeA celiac artery, SpA splenic artery, CHA common hepatic artery, RGEA right gastroepiploic artery, SMA superior mesenteric artery, DPA dorsal pancreatic artery, MCA middle colic artery, J1A first jejunal artery, IPDA inferior pancreaticoduodenal artery

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  Fig. 3. Preoperative CT and schema. A Abdominal contrast-enhanced CT sagittal image, B schema. The tumor was located on the ventral side of pancreas. Transverse colon and transverse mesocolon were displaced dorsally and stomach and greater omentum were compressed ventrally by the tumor. Based on its localization and vascular supply, the tumor was considered to originate from the peripancreatic fat tissue and situated in the retroperitoneum

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  Fig. 4. Intraoperative photographs. A The tumor was yellow and approximately size of an adult’s head. B We dissected of the transverse mesocolon (dotted white circle) and ligated drainage vein (black arrows) at the site where it flows into the transverse mesocolon. C We identified the feeding artery at the lower border of the pancreas (white arrows). D, E (Schema): after tumor resection, we clarified the relationship between the feeding artery (white arrows) and other vessels. We also removed the portion of the pancreatic capsule and the transverse mesocolon attached to the tumor, which were considered to be the origin of the tumor (dotted black circle). RGEV right gastroepiploic vein, DPA dorsal pancreatic artery, AcRCV accessary right colic vein, MCA middle colic artery, MCV middle colic vein

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  Fig. 5. Resected specimen. The size of tumor was 34 × 23 × 7 cm, and its weight was 2590 g. Although the tumor had a thin fibrous capsule, we were able to resect it without injuring the capsule

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  Fig. 6. Histopathological and immunohistochemical examinations. A, B: Hematoxylin and eosin stain (×20). The tumor was mostly composed of slightly enlarged adipocytes of varying sizes, along with atypical stromal cells and lipoblast (dotted black circle). C CDK4 positive, D MDM2 positive, E p16 positive, F CD34 weak positive, G S-100 weak positive, H Ki-67 index of 2%. The tumor was diagnosed as a well-differentiated liposarcoma

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  Fig. 7. Schema. A Embryonic anatomy, B Our case. The tumor was supplied by a branch of the DPA, suggesting its origin in the peripancreatic fat tissue (star). Therefore, we considered that the tumor extended from the peripancreatic fat tissue toward the space between the greater omentum and transverse mesocolon. CHA common hepatic artery, DPA dorsal pancreatic artery