case_images: PMC11322092_01
case_images: Findings of the first computed tomography scan of a 9-year-old cat presenting with recurrent ascites of unknown etiology. Triphasic images before (A) and after (B) imaging in the ventrodorsal position. (A) Pre-contrast stage, (B) arterial phase, (C) venous phase, (D) delayed phase. A mass showing connectivity with the left leg of the pancreas was observed; it was ill-defined, amorphous with an irregular margin, and an ambiguous ventral margin. No significant internal contrast enhancement was observed in any phase after imaging, and it was homogenously hypodense compared with normal pancreatic parenchyma.
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case_images: PMC11322092_01_fvets-11-1406223-g001.jpg
case_images: fig1
case_images: A mass demonstrating connectivity with the left leg of the pancreas was identified (Figure 1). The mesentery and fat tissue were hyperechoic and edematous (Supplementary Figure S1).
case_images: Findings of the first computed tomography scan of a 9-year-old cat presenting with recurrent ascites of unknown etiology. Triphasic images from delay phase in the dorsal plane (A-C). (A) The right leg of the pancreas was well observed with relatively normal shape and strong contrast enhancement (green circle). (B) After imaging, the periphery of the mass received blood flow from the splenic artery, which branches from the celiac artery, and rim enhancement (orange circle) was observed in the portal vein and lag phase. (C) Intra-abdominal lymph nodes showed homogenous contrast enhancement (red circle) with mild hypertrophy while maintaining their normal shape.
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case_images: PMC11322092_01_fvets-11-1406223-g002.jpg
case_images: fig2
case_images: Severe fat-stranding was observed around the mass, involving the surrounding peritoneum with nodules in a diffusely aggregated pattern, presumably due to fat necrosis (Figure 2). The peritoneal fluid appeared reddish and cloudy upon macroscopic examination (Supplementary Figure S2A). Cytological examination of the peritoneal fluid revealed modified transudate, predominantly composed of neutrophils and macrophages, with visible lymphoid cells (total nucleated cell count, 2,680 cells/muL; total protein: 3.4 mg/dL) (Supplementary Figure S2B).
case_images: Histopathological and immunohistochemical evaluation of a pancreatic tumor in a cat. (A) The mass was composed of extensive adipose tissue (arrow), locally extensive inflammatory infiltrates, fibrous connective tissue (asterisk), and small invasive proliferative glands (arrowhead). (B) Well-defined small irregular glands composed of single-layered epithelial cells (arrowhead) were surrounded by abundant desmoplastic stroma (asterisk). (C) H&E staining shows normal pancreatic tissue on the left and a pancreatic tumor on the right. (D) In immunohistochemistry, the normal pancreatic ducts (arrows) on the left were positive for pancytokeratin. Consistently, neoplastic glands (arrowhead) on the right were positive for pancytokeratin. (E) Visceral peritoneum was thickened by sclerotic fibrous connective tissue (arrowhead). (F) Collagen, fibrin, and neovascularization were increased in peritoneum that had denuded mesothelium. (G) Lymphocytic inflammatory cells (asterisk) were infiltrated in sclerotic stroma.
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case_images: fig3
case_images: Possible compression of the splenic vein by the mass was considered (Supplementary Figure S3). Histopathologically, the pancreatic mass was composed of extensive adipose tissue, locally extensive infiltrates of phagocytizing macrophages, fibrous connective tissue, and small invasive proliferative glands (Figure 3A). The mass showed a typical histomorphology of pancreatic ductal adenocarcinoma with well-defined, small, irregular glands composed of single-layer ductal epithelial-like cells surrounded by abundant desmoplastic stroma (Figures 3B,C). Normal pancreatic ducts were positive for pancytokeratin, and the neoplastic glands were consistently positive for pancytokeratin (Figure 3D), further suggesting the tumor to be of the pancreatic ductal origin. In addition, lymphocytic inflammatory cells infiltration, increased collagen, fibrin, and neovascularization, and denuded mesothelium were observed in visceral peritoneum, indicating the presence of SEP (Figures 3E-G).
case_images: Histopathological evaluation of the metastases of pancreatic adenocarcinoma of presumed origin in the cat. Extensive implantation of neoplastic nodules (arrowhead) with desmoplasia (asterisk) was observed in the (A) liver and (B) urinary bladder. (C) The pulmonary blood vessel was filled with tumor emboli.
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case_images: PMC11322092_01_fvets-11-1406223-g004.jpg
case_images: fig4
case_images: The falciform ligament was sclerosing and thickened (Supplementary Figure S4). In addition, fibrinous adhesion of the thickened abdominal wall with adjacent organs (Supplementary Figure S4B) and a substantial amount of ascites were observed. Extensive implantation of neoplastic nodules with desmoplasia was observed in the liver, stomach, peritoneum, mesentery, mesenteric lymph nodes, and urinary bladder (Figures 4A,B). Tumor emboli were also observed in the pulmonary blood vessels (Figure 4C).