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Abstract
Background/Aims
Gastric schwannoma (GS), a rare neurogenic mesenchymal tumor, is usually benign, slow-growing, and asymptomatic. However, GS is often misdiagnosed as gastrointestinal stromal tumors (GIST) on endoscopic and radiological examinations. The purpose of this study was to evaluate EUS characteristics of GS distinguished from GIST.
Methods
A total of 119 gastric subepithelial lesions, including 31 GSs and 88 GISTs, who were histologically identified and underwent EUS, were enrolled in this study. We evaluated the EUS characteristics, including location, size, gross morphology, mucosal lesion, layer of origin, border, echogenic pattern, marginal halo, and presence of an internal echoic lesion by retrospective review of the medical records.
Results
GS patients comprised nine males and 22 females, indicating female predominance. In the gross morphology according to Yamada's classification, type I was predominant in GS and type III was predominant in GIST. In location, GSs were predominantly located in the gastric body and GISTs were predominantly located in the cardia or fundus. The frequency of 4th layer origin and isoechogenicity as compared to the echogenicity of proper muscle layer was significantly more common in GS than GIST. Although not statistically significant, marginal halo was more frequent in GS than GIST. The presence of an internal echoic lesion was significantly more common in GIST than GS.
References
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Fig. 1.
Endoscopic (A) and endosonographic (B) findings in a 59-year-old woman with a gastric schwannoma. (A) Endoscopy shows a submucosal elevated lesion with type I morphology according to Yamada's classification in the greater curvature of the body. (B) On EUS, the mass is homogeneous and its echogenicity is similar to that of the normal proper muscle layer (black arrows). It measures 32.0×21.0 mm in size and a marginal halo (white arrows) is observed.
Fig. 2.
Endoscopic (A) and endosonographic (B) findings in a 66-year-old woman with a gastrointestinal stromal tumor. (A) Endoscopy shows a submucosal elevated lesion with type III morphology according to Yamada's classification in the cardia. (B) On EUS, the mass is homogeneous and its echogenicity is higher than that of the normal proper muscle layer (black arrows). It measures 20.0×16.0 mm in size and a marginal halo (white arrows) is observed.
Table 1.
Baseline Characteristics of the Patients with GSs and GISTs of the Stomach
Table 2.
Endoscopic Features of the Patients with GSs and GISTs of the Stomach
| Variable | GS (n=31) | GIST (n=88) p-value |
|---|---|---|
| Shape | 0.062 | |
| Round to ovoid | 31 (100) | 78 (88.6) |
| Lobulated | 0 (0) | 10 (11.4) |
| Mucosal lesion | 1.000 | |
| Present | 5 (16.1) | 14 (15.9) |
| Absent | 26 (83.9) | 74 (84.1) |
| Morphology (Yamada's classification) a | 0.030 | |
| Type I | 16 (51.6) | 26 (29.5) |
| Type II | 12 (38.7) | 35 (39.8) |
| Type III | 3 (9.7) | 27 (30.7) |
| Type IV | 0 (0) | 0 (0) |
| Location | 0.001 | |
| Body, GC | 19 (61.3) | 21 (23.9) |
| Body, LC | 9 (29.0) | 24 (27.3) |
| Cardia/fundus | 1 (3.2) | 37 (42.0) |
| Antrum | 2 (6.5) | 6 (6.8) |
a Yamada type I is elevated, with an indistinct border; Type II is elevated with a distinct border at the base but no notch; Type III is elevated, but no peduncle; Type IV is pedunculated and elevated. GS, gastric schwannoma; GIST, gastrointestinal stromal tumor; GC, greater curvature; LC, lesser curvature.
Table 3.
Endoscopic Ultrasonography Features of the Patients with GSs and GISTs of the Stomach
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