Misdiagnosis of pancreatic metastasis from renal cell carcinoma: A case report

Figure 1 Sonogram imagine. A: B-mode; B: Contrast-enhanced ultrasound. There is a hypoechoic lesion (arrow) in the pancreatic head, with high and inhomogeneous enhancement.

Figure 2 Abdominal computed tomography. A: Plain scan; B: Arterial phase; C: Coronal plane; D: Venous phase; and E: Delayed phase. A low-density mass is seen (arrow). There is marked heterogeneous enhancement in the “fast in and fast out” mode; multiple tortuous blood vessels are present at the periphery and small patchy non-enhancing areas in the middle (indicating necrosis). There is moderately decreased enhancement in the venous and delayed phases.

Figure 3 Abdominal magnetic resonance imaging. A: T1W in-phase; B: out-of-phase images show a well-defined mass (arrow) in the pancreatic head, with signal loss on out-of-phase images for intracellular fat (arrow); C: Diffusion-weighted image (b 800 s/mm²); D: Increased signal (arrow), with a corresponding low signal on the apparent diffusion coefficient map; E and F: T1W FS contrast-enhanced images show marked heterogeneous enhancement in the arterial phase, with wash out in venous phase (though the thin hyperintense rim persists); and G: Magnetic resonance cholangiogram shows a dilated common bile duct and main pancreatic duct.

Figure 4 Postoperative histopathology of the resected specimen. A: The pancreatic mass shows hemorrhagic and necrotic changes; there is a thin fibrous capsule (arrow); B: Stained section shows large polygonal cells with clear cytoplasm, arranged in an alveolar pattern; the cells have uniform round nuclei with inconspicuous nucleoli (hematoxylin and eosin, × 100, inset × 400); and C: Immunohistochemistry shows the tumor cells to be positive for vimentin, CD10, and PAX-8, and negative for CK7.