GASTROENTEROLOGY ARTICLE OF THE WEEK
February 5, 2004
Hwang JH, Kimmey MB. The incidental upper gastroeintestinal subepithelial mass. Gastroenterology 2004;126:301-307.
1. Gastrointestinal stromal tumors (GISTs)
a. are the most commonly identified intramural subepithelial mass in the upper GI
tract
b. 10 to 30% may be malignant
c. represent smooth muscle tumors
d. express CD 117, indicating origin from the interstitial cells of Cajal
e. can be easily confused with leiomyomas
f. are most commonly located in the esophagus
g. arise from the muscularis propria, can be diagnosed with endoscopic biopsies
2. EUS of subepithelial lesions
a. anechoic masses with no Doppler signal are usually duplication cysts
b. hypoechoic submucosal masses are usually lipomas
c. well circumscribed lesions are usually benign
d. GISTs are hypoechoic and usually arise from layer 4
3. Immunohistochemical staining of EUS-FNA material:
a. positive staining with CD-117 (c-kit) suggests a GIST
b. positive staining with CD-34 excludes a GIST
c. positive smooth muscle actin suggests leimyoma
d. positive S-100 suggests a neural origin
True or False
4. Subepithelial lesions that are >1cm in diameter and do not have the typical features of a lipoma should undergo EUS examination
5. Mass, bulge or impression with normal overlying mucosa identified during endoscopy should be described as a subepithelial rather than submucosal mass.
6. GISTs in the lower GI tract may have a higher malignant potential, even when small in size.
7. Endoscopic biopsies of the normal mucosa overlying subepithelial masses should not be done as they do not help in the diagnosis.
8. Endoscopic submucosal resection is a safe method for removing small GISTs located on layer 4.
9. GISTs >3cm in diameter should be surgically removed.
10. Subepithelial masses <1cm in diameter are rarely of clinical significance, further evaluation should consist of a repeat endoscopy in 1 year.
11. When probed with closed endoscopy forceps, GISTs are soft and mobile.
12. EUS-FNA is a useful tool to detect the malignant potential of GISTs
13. A 4cm hypoechoic mass
originating from layer #4 should undergo EUS-guided FNA prior to surgical
removal.