case_images: PMC11184913_01
case_images: Ultrasound and macroscopic features of the hepatic vascular hamartoma. (A,B) The hepatic cysts are anechoic and homogeneous with a septate architecture. (C) Gross features of the vascular hamartoma consisting of multiple cystic-like structures, appearing red-brown in color and involving the right medial lobe of the liver, accompanied by severe atrophy of the surrounding hepatic parenchyma (arrow) (D).
case_images: fvets-11-1404164-g001.jpg
case_images: PMC11184913_01_fvets-11-1404164-g001.jpg
case_images: fig1
case_images: The first cyst-like structure had an irregular shape, thin-walled and fluid-filled appearance, and the other two masses were anechoic with thin internal septations (Figures 1A,B). Upon retracting the omentum, a multilobulated cyst-like structure was exposed (Figure 1C). Two circumferential ligatures monofilament (polydioxanone 2/0) sutures were placed around the right medial lobe near the vascular pedicle and partial lobectomy was made (Figure 1D). The adjacent parenchyma was mechanically compressed and atrophied by the cystic structures (Figure 1D).
case_images: PMC11184913_02
case_images: Photomicrographs of hepatic vascular hamartoma in an 8-month-old cat. (A) The hepatic mass is composed of multiple cystic-like structures containing blood, compressing the adjacent parenchyma, H&E stain, bar = 2 mm. (B) The vascular spaces exhibit characteristics of well-differentiated arterioles and venules of varying sizes lined by endothelium (black arrow), H&E stain, bar = 50 mum. (C) Interspersed with these structures there are clusters of atrophied hepatocytes (black arrow), H&E stain, bar = 200 mum. (D) A moderate amount of fibrous tissue confirmed by MT stain (and the inset) is present, bar = 500 mum. (E) The cells lining the cystic structures demonstrate positive immunodepression for vimentin (black arrow) and negative immunoexpression for PanCK (black arrow) (F), IHC, bar = 100 mum. The positive inner control for PanCK was the bile ducts (white arrow) and the negative inner control for PanCK was the small artery (blue arrow), IHC, bar = 100 mum (F).
case_images: fvets-11-1404164-g002.jpg
case_images: PMC11184913_02_fvets-11-1404164-g002.jpg
case_images: fig2
case_images: Histologically, the hepatic parenchyma was focally compressed by a well-delimited, expansile, unencapsulated cavernous mass (Figure 2A), composed of variably sized blood channels. The vascular spaces appeared consistent with well-differentiated variable-sized arterioles and venules (Figure 2B). Small clusters of hepatocytes were interspersed among the cystic structures, admixed with a moderate amount of fibrous tissue, composed of tightly packed fibroblasts and numerous collagen fibers (Figures 2C,D). Immunohistochemically, the lining cells (interpreted as endothelial cells) of the cavernous spaces exhibited a strong diffuse cytoplasmic immunolabeling for vimentin (Figure 2E) and negative immunoexpression for PanCK (Figure 2F).
case_images: Photomicrographs of the hepatic biliary ductal hamartoma in a 12-year-old cat. (A) Multiple variable-sized cyst-like structures are present within the hepatic parenchyma, H&E stain, bar = 2 mm. (B) The cysts contain a pale homogeneous eosinophilic material and are lined by a single layer of epithelial cuboidal cells, H&E stain, bar = 50 mum. (C) Moderate hepatocellular vacuolar degeneration, lymphoplasmacytic infiltrate, and fibrous tissue are present between the components of the hamartoma (star), H&E stain, bar = 50 mum. (D) The epithelial cells show positive immunoexpression for PanCK (white arrow) and negative immunolabeling for vimentin (black arrow, inner positive control), IHC, bar = 200 mum.
case_images: fvets-11-1404164-g003.jpg
case_images: PMC11184913_02_fvets-11-1404164-g003.jpg
case_images: fig3
case_images: In contrast, in the biliary duct hamartoma (Figure 3A) the cystic structures contained a pale eosinophilic homogeneous material and were lined by a single layer of cuboidal to flattened epithelial cells (Figure 3B), showing a strong diffuse cytoplasmic immunolabeling for PanCK (Figure 3D) and negative immunolabeling for vimentin. The adjacent parenchyma exhibited moderate degenerative changes accompanied by a moderate inflammatory infiltrate, composed of lymphocytes and plasma cells, admixed with moderate amounts of fibrous tissue (Figure 3C).