Primary leiomyosarcoma of the portal vein: A progressively enhancing fusiform mass without biliary dilatation as a rare differential for hilar tumors

Figures

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  Fig. 1. Dynamic CE-CT findings. (A) Unenhanced, (B) arterial, (C) portal venous, and (D) delayed phase images. Unenhanced CT demonstrates a 45-mm low-attenuation mass at the hepatic hilum (yellow arrow). The lesion exhibits heterogeneous and progressively increasing enhancement. Cavernous transformation of the portal vein at the hepatic hilum is also observed (pink arrowheads). The reconstructed view (E) clearly demonstrates the fusiform intraluminal configuration of the tumor and precisely depicts its anatomical relationship to the main portal trunk and the right and left portal branches (blue arrows). PV: portal vein.

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  Fig. 2. MRI findings. (A) T2-weighted image (T2WI), (B) in-phase and (C) out-of-phase T1-weighted images (T1WI), (D) diffusion-weighted image (DWI), (E) apparent diffusion coefficient (ADC) map, and (F) hepatobiliary phase of gadoxetic acid–enhanced MRI. The mass demonstrates well-defined margins and a fusiform configuration. It appears heterogeneously hypointense on T2WI and homogeneously hypointense on T1WI, with no apparent fat component. The lesion exhibits restricted diffusion. In the hepatobiliary phase (F), the tumor appears hypointense.

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  Fig. 3. Macroscopic findings. A whitish mass (asterisk) occupying the lumen of the right portal vein, arising from the main portal vein trunk (A), compressing and flattening the extrahepatic bile duct (arrow) without macroscopic evidence of direct invasion (B). The arrowhead indicates the right hepatic duct.

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  Fig. 4. Hematoxylin and eosin staining findings. The tumor is composed of intersecting fascicles of spindle-shaped cells with brightly eosinophilic cytoplasm (A). The tumor shows marked heterogeneity, containing areas with only mild nuclear atypia (B) and regions with severe atypia (C). Focal necrosis is also observed (D). Scale bars: 100 µm (A, B, C), 250 µm (D).

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  Fig. 5. Histological and immunohistochemical findings. (A) Hematoxylin and eosin staining. (B) Desmin staining. (C) α-smooth muscle actin (α-SMA) staining. (D) h-caldesmon staining. Scale bars: 250 µm (A, B, C, D). The tumor cells stain positive for all markers, supporting smooth muscle differentiation.

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  Fig. 6. EVG staining. The tumor (asterisk) arises within the tunica media (arrowhead) of the portal vein and exhibits an expansile growth pattern that distends the vessel wall. The arrows indicate the tunica intima.