Fact-sheet: Gastrointestinal stromal tumor -GIST
Updated on 02/18/2020 at 1:14 PM
View all RADEOS cases associated with this fact-sheet
Definition
GIST = Gastro-Intestinal Stromal Tumor:
group of mesenchymal tumors of the digestive tract composed of spindle cells expressing CD117 (or "C-kit protein")
Can affect the entire digestive tract but preferentially the Stomach ++.
Clinical features
- Age at diagnosis around 60 years
- Abdominal pain
- Gastrointestinal bleeding
- Bowel obstruction is extremely rare given the submucosal location of the tumor
Ultrasound
- Mass often large, as it is generally extraluminal, with nonspecific central tumoral necrosis
- Possible endoluminal growth pattern
- No thickening at the intestinal attachment point
- Preservation of the hyperechoic submucosa
- Doppler: hypervascularization
CT
- Large lesion (often 5-10 cm) with well-defined margins
- Submucosal location
- Hyperdense calcifications
- Heterogeneous enhancement after contrast injection: hypodense necrotic center and hyperdense areas
Lymph node involvement virtually absent
MRI
- T1: large submucosal mass
- T2: hyperintense signal with heterogeneous areas
- Markedly hyperintense fluid signal in case of necrosis
- After Gadolinium injection: marked enhancement
Vascular intervention
Arteriography: delineates the vascular pedicle
US- or CT-guided biopsy before potential preoperative chemotherapy
Management
En bloc surgery
TKI treatment (Glivec)
Testing for c-KIT and PDGFRalpha mutations for use of targeted therapies
Classification
Miettinen classification
Differential diagnosis
Digestive lymphoma (generally hypervascular)
Carcinoid tumor (hypervascular, presenting thickening at the point of attachment)
Small bowel metastases (melanoma, colorectal ADK)
