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case_images: Esophagogastroduodenoscopy upon admission to hospital showing a large, lobulated subepithelial lesion with a fistulous hole in the second portion of the duodenum.
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case_images: An upper gastrointestinal endoscopy revealed a subepithelial mass with a fistulous hole on the second portion of the duodenum (Fig. 1).
case_images: Computed tomography scan of the abdomen upon admission to hospital. (A) Large lobulated and heterogeneously enhanced mass (11.5x9.3 cm) with internal necrosis. An air-fluid level was noted on the pancreaticoduodenal groove and the internal cavity of the mass was connected to the second portion of the duodenum (arrow). (B) An Ill-defined low density lesion was noted at hepatic segment eight, abutting the bile duct and hepatic artery. The right intrahepatic duct was marginally dilated by the lesion.
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case_images: A computed tomography (CT) scan, which was acquired from the referring local clinic (Choi Kang Sik Internal Medicine, Seoul, Republic of Korea), demonstrated a large, heterogeneously enhanced lobulated mass (11.5x9.3 cm; longest diameter x greatest perpendicular diameter) with internal necrosis at the pancreaticoduodenal groove (Fig. 2A). Furthermore, an ill-defined low-attenuation lesion was identified at segment eight of the liver, abutting the bile duct and hepatic artery (Fig. 2B).
case_images: Histopathological findings of the duodenal mass. (A) Hematoxylin and eosin staining shows whirling sheets of spindle-shaped cells, which are consistent with gastrointestinal stromal tumor (magnification, x40). (B) Immunohistochemical staining demonstrates that the tumor cells were positive for c-Kit (CD117).
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case_images: An ultrasound-guided needle biopsy of the duodenal mass was performed and pathological examination identified whirling sheets of spindle-shaped cells (Fig. 3A). Immunohistochemical staining was positive for c-Kit, but negative for cluster of differentiation 34, S-100 and desmin (Fig. 3B).
case_images: Computed tomography scan of abdomen following seven weeks of imatinib treatment. The previously noted hepatic mass had increased in size and the right intrahepatic duct dilatation was aggravated by the mass.
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case_images: However, the hepatic mass had increased from 1.7x1.5 cm to 3.9x3.2 cm in diameter (longest diameter x greatest perpendicular diameter) and the right hepatic duct was markedly dilated by the mass (Fig. 4).
case_images: Histopathological findings of the hepatic mass. (A) Hematoxylin and eosin staining shows gland-forming malignant cells with hyperchromatic and prominent nuclei, which is consistent with a moderately differentiated adenocarcinoma (magnification, x40). Immunohistochemical staining demonstrates that the tumor cells were (B) negative for c-Kit and (C) positive for cytokeratin 19.
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case_images: Immunohistochemical analysis exhibited c-Kit-negative and cytokeratin 19-positive staining (Fig. 5).