1. Subepithelial tumors in the upper gastrointestinal tract
Staff lecture
Subepithelial tumors in the upper gastrointestinal tract
Jung-Wook Kim

2. M/66, 건강검진 Next step? Biopsy EUS or CT Resection
Observation & regular follow up

3. F/74, Abdominal discomfort
다음 검사는?
치료는?

4. Overview Definition Epidemiology Clinical features Diagnosis
Natural history
Management

5. Definition
SMT
SET

6. Definition SMT SET Subepithelial tumor (SET)
Mass lesion appearing as mass, bulge, or impression covered with normal appearing overlying mucosa
Included both those of intramural or extramural origin
Mass can arise from outside the wall or from layers other than the submucosa.
→ The term subepithelial is favored than submucosal
SMT
SET

7. Epidemiology Prevalence in upper GI endoscopy: 0.36%
- 8-year data, retrospective study
- 54 out of endoscopy
Equal frequency in both sexes
Generally after the fifth decade
Surg Endosc 1991;5:20-23

8. Clinical Features Majority of SET Large SET Firm SET Asymptomatic
Discovered incidentally during endoscopy
Large SET
May outgrow their blood supply → ulcerate the mucosa → present with upper GI bleeding
Firm SET
Can cause obstructive Sx: GE junction or pylorus
Jaundice and pancreatitis: papilla
Surg Endosc 1991;5:20-23
J Gastroenterol Hepatol 2008;23:

9. M/64, Alcoholic LC, melena

10. F/49, Vomiting

11. Cross sectional imaging
Diagnostic Tools
Endoscopy
EUS
Histologic Diagnosis
Cytology
Histology
Immunohistochemistry
Surgical specimen
Cross sectional imaging
Ultrasound

12. Endoscopy Size estimation Intramural vs Extramural Type of SET
Open biopsy forceps
Intramural vs Extramural
Suboptimal in identifying the origin
Overall accuracy of 89% (sensitivity 98%, specificity 68%)
Type of SET
Lipoma (yellowish, pillow or cushion sign)
Ectopic pancreas (antrum, umbilication)
Mucosal biopsies
To confirm that the mucosa is histologically normal
Carcinoid tumor

13. Endoscopy
Color
Size
Consistency

14. Ectopic pancreas

15. Pillow sign (+)

16. Endoscopy (size)
Gastrointest Endosc 2005;62:202-8

17. EUS Most accurate method for characterizing SET
Reliably distinguish intra- vs extramural
Large lesions which extend beyond the penetration depth of the ultrasound cannot be accurately measured.
High accurate in predicting the size
(compared to the surgical pathology)

18. EUS Layer of origin Size Echotexture Border Internal structure1
Layer of origin 2
Size 3
Echotexture 4
Border 5
Internal structure 6
Vascularization 7
Lymphadenopathy

19. Normal five-layered wall structure
1st mucosa
2st muscularis mucosa
3rd submucosa (SM)
4th muscularis propria (MP)
5th Serosa

20. ① ② ③ ④ ⑤ Granular cell tumor carcinoid Varix, cyst leiomyoma GIST
Lymphangioma
Ectopic pancreas
lipoma ③
Varix, cyst
GIST
leiomyoma ④ ⑤

21. EUS (Layer of origin) 4. Muscularis propria 2. Muscularis mucosa
3. Submucosa

22. EUS (intra- vs extramural)

23. Extrinsic compression (esophagus)
Normal organ and structure
Upper/lower esophageal sphincter
Vascualr structure; aortic arch, heart
Left main bronchus
Vertebra
Pathologic lesion
Aneurysm
Vascular abnormalities
Left atrial dilatation
Mediastinal LAP/tumor
Lung cancer
Lymphoma

24. Extrinsic compression (stomach)
Normal structure;
Spleen (m/c): gastric fundus or upper corpus
Vascular structures in splenic hilum
Left lobe of the liver
GB: antrum
The images of temporary compression: intestinal loops
Tail of pancreas
Abnormal structure
Pancreatic pseudocyst
Aortic aneurysms
Left atrial dilatation

25. F/55, SET?
Hepatic hemangioma

26. EUS (Echotexture) Generally Suggestive of malignancy in GIST
Hypoechoic: Leiomyoma / GIST
Anechoic: cystic lesions
Hyperechoic: lipomas
Suggestive of malignancy in GIST
Size > 3cm
Cystic space
Echogenic foci
Adjacent malignant-appearing lymph nodes

27. EUS (Echotexture)
Mesenchymal tumor
Lipoma
Cyst

28. Extrinsic compression
EUS
Interpretation of the EUS images is operator dependent.
High agreement
Cystic lesion
Lipoma
Extrinsic compression
Vascular lesions
Leiomyoma or GIST
Carcinoid
Pancreatic rest
Metastatic lesions
Poor agreement

29. Histologic diagnosis Cytology Histology Immunohistochemisty
Tissue can be obtained for histology in a number of ways;
Stacked ‘jumbo’ forceps
Trucut style biopsy
EMR
ESD
Surgical resection

30. Histologic diagnosis Bite on bite
Removal of overlying mucosa and SM by strip biopsy
Bleeding risk
Insufficient tissue for pathologic diagnosis or counting of mitotic index

31. Management of SETs
악성화 가능성?
자연 경과는?
치료 방법은? (수술 or 내시경적 절제)

32. Common SET in stomach GIST Leiomyoma Schwannoma Lymphangioma
Carcinoid tumor
Ectopic pancreas
Lipoma
Malignant potential
Benign

33. GIST
The most common intramural subepithelial lesion encountered during upper GI endoscopy
Originated from the intestitial cells of Cajal
Kit expression
C-kit (CD117) / CD 34 (+)
Desmin negative
2nd (muscularis mucosa) or 4th (muscularis propria)
Well-defined border
Hypoechoic
Homogenous

35. GIST 10~30%; malignant Characteristics of malignant GIST
Mitotic index and dimension of lesion
No lesion can be definitively labeled as benign
Characteristics of malignant GIST
Heterogenous structure
Hyperechoic foci and/or anechoic necrotic areas
Irregular extraluminal border
Associated LAP with malignant features
Large dimension (> 4cm)

36. GIST (risk stratification)
Hum Pathol 2007;38:

37. Malignant risk of GIST Very low < 1% Low 1-10% Moderate 10-50%
High >50%

38. Neuroendocrine tumors (carcinoid)
Originate from enterochromaffin-like cells located in the gastric mucosa
2nd or 3rd layer
Homogenous, well-defined border, hypoechoic /isoechoic
Malignant potential is present
EMR
< 2 cm
3rd layer
No associated LAP

40. Natural course of incidental SETs
Follow up
(84 months)
8mm in initial mean size
- Moderate risk GIST (2, 0.8%)
- Schwannoma (1)
World J Gastroenterol 2010;16:

41. Natural course of incidental SETs
Retrospective study
989 SETs (≤ 30 mm), f/u median 24 months (3-123mo)
84 (8.5%): significant change (size, EUS/endoscopic findings)
→ 25 (2.5%): endoscopic/surgical resection
→ 19 (1.9%) GIST (3 high risk)
J Clin Gastroenterol 2011;45:

42. Mx algorithm in SETs SET < 1cm Consider EGD f/u in 6 mo or 1 year
lipoma
Extramural
Lipoma
Vascular lesion
cyst or lymphangioma…
EUS
> 3 (2) cm
Hypoechoic
Surgery
Dependent on clinical availability and risk
1~3rd layer: endoscopic resection
4th layer
- < 2cm: follow up
- > 2cm: punctured by EUS

43. M/66, 건강검진 Next step? Biopsy EUS or CT Resection
Observation & regular follow up

44. F/74, Abdominal discomfort
다음 검사는?
치료는?
EUS

45. F/74, Abdominal discomfort
3.8x3.0cm
→ Wedge resection → GIST, low risk