PMC5399200_01
(A) Abdominal dynamic computed tomography (CT) shows a 4-cm-diameter mass in the mesentery near the third portion of the duodenum and ligament of Treitz at the initial observation (arrow). (B) Magnetic resonance imaging shows the mass to be heterogeneous with high signal intensity on T2-weighted imaging at the initial observation (arrowhead). (C) Abdominal dynamic CT shows the mass to have grown in size to a diameter of 13 cm at 16 months after the initial observation. (D) 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) shows moderate and heterogeneous 18F-FDG uptake by the mass.
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An abdominal dynamic computed tomography (CT) scan showed a 4-cm-diameter, partially ill-defined mass with delayed enhancement in the mesentery near the third portion of the duodenum (Fig. 1A). Magnetic resonance imaging (MRI) revealed the mass to be hypointense on T1-weighted imaging (T1WI) and heterogeneous with high intensity on T2-weighted imaging (T2WI) (Fig. 1B). CT showed that the mass had increased in size and was now 13 cm in diameter (Fig. 1C). 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) revealed moderate and heterogeneous 18F-FDG uptake by the mass (Fig. 1D). There was a low-to-moderate percentage of spindle cells with nuclear atypia, and the percentage of mitotic figures was low (0-1/50 high power fields).
The tumor, measuring 14.7 cm in the greatest dimension, is rounded in shape. The mesenteric margin is ill-defined (arrows).
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The mesenteric margin was ill-defined (Fig. 2). There was a low-to-moderate percentage of spindle cells with nuclear atypia, and the percentage of mitotic figures was low (0-1/50 high power fields).
Sections stained with hematoxylin and eosin show that the tumor is mainly composed of spindle-shaped cells with a fibrous and myxoid stroma (A), partially infiltrating the muscularis propria and subserosa of the small bowel (arrow) (B). (C) The tumor cells appear immunohistochemically positive for beta-catenin and platelet-derived growth factor (PDGFR) -beta, but negative for c-Kit and CD34. Original magnification, x40 (A and C) and x4 (B).
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A histological examination revealed that the tumor was mainly composed of spindle-shaped cells with a fibrous and myxoid stroma (Fig. 3A), partially infiltrating the muscularis propria and subserosa of the small bowel (Fig. 3B). There was a low-to-moderate percentage of spindle cells with nuclear atypia, and the percentage of mitotic figures was low (0-1/50 high power fields). Immunohistochemistry showed that the tumor cells were positive for beta-catenin and platelet-derived growth factor (PDGFR)-beta, but negative for c-Kit and CD34 (Fig. 3C).