PMC5440794_01
Endoscopic (a) and endosonographic (b) findings in the current case of gastric schwannoma. (a) A round, submucosal mass with an indistinct border was observed at the lesser curvature of the gastric body. (b) On endoscopic ultrasonography, the lesion (white arrow) appeared homogeneous and its echogenicity was lower than that of the normal muscle layer. The mass measured 3.7 x 3.2 cm and originated from the fourth layer.
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EGD revealed a submucosal bulge on the anterior wall of the gastric body (Figure 1(a)). The features of the mass were similar to those of a gastrointestinal stromal tumor (GIST) (Figure 1(b)).
Computed tomography (CT) image of the gastric schwannoma. (a) An oval-shaped mass (white arrow) with a size of 43 x 32 mm was observed in the lesser curvature of the stomach, which exhibited a slightly low density on plain scanning CT imaging. (b) The CT value of the mass was about 38 HU before the injection of contrast medium. The mass showed delayed enhancement with a CT value of 53 HU on arterial-phase enhanced CT scanning. (c) The CT value of the mass was slightly increased (68 HU) on portal venous-phase enhanced CT imaging. (d) The CT value of the mass was increased (78 HU) on delayed enhanced CT scanning after a delay of 3 minutes.
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The mass was partly exophytic and partly projected into the gastric lumen, causing smooth indentation, and measured 4.3 x 3.2 cm (Figure 2).
Pathological imaging of the mass. (a) An exophytic tumor with size of 4 x 3 cm arising from the anterior wall of the lesser gastric curvature was observed. The exophytic part of the mass appeared off-white in color and rough with a concavo-convex surface; however, the margin of the mass on the gastric wall was clear. (b) Hematoxylin and eosin staining showed that the mass was composed of palisade-arranged spindle cells and peritumoral cuff-like lymphocytic infiltration (white arrow). (c) Immunohistochemical staining of sections showed that the gastric schwannoma was S-100-positive but was negative for (d) CD34, (e) CD117, (f) desmin, (g) DOG1, (h) Ki-67, and (i) SMA. x100 magnification for all micrographs.
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The exophytic part of the mass appeared off-white in color and rough, with a concavo-convex surface; however, the margin of the mass on the gastric wall was clear (Figure 3(a)). Histopathology revealed that the tumor was composed of spindle cells in a palisading arrangement, and peritumoral cuff-like lymphocytic infiltration was also observed (Figure 3(b)). Immunohistochemical (IHC) staining showed that the spindle cells were positive for S-100 (Figure 3(c)) and negative for CD34, CD117, desmin, DOG1, Ki-67, and smooth muscle actin (SMA) (Figures 3(d)-3(i)), which confirmed a diagnosis of GS.