Gastrointestinal Stromal Tumor (GIST)
Grading / Staging / Report
Grading
Risk for Metastasis/Progressive Disease| Stomach | Duodenum | Jejunum & Ileum | Rectum | |
|---|---|---|---|---|
| ≤5 mits/50 hpf | ||||
| ≤2cm | 0 none | 0 none | 0 none | 0 none |
| >2cm ≤5cm | very low | low | low | low |
| >5cm ≤10cm | low | high | moderate | high |
| >10cm | moderate | high | high | high |
| >5 mits/50 hpf | ||||
| ≤2cm | few cases | no cases | few cases | high |
| >2cm ≤5cm | moderate | high | high | high |
| >5cm ≤10cm | high | high | high | high |
| >10cm | high | high | high | high |
Esophageal tumors are too rare to develop criteria
With wide field microscope view, count 25 fields with same cutoff of 5 as above
Based on Miettinen and Lasota 2006
Progressive Disease or Death Risk Groups
| Group | Approximate Progression Incidence |
|---|---|
| 0 None | 0 |
| Very low | <2% |
| Low | <5% |
| Moderate | 10-30% |
| High | >50% |
Staging
- See 7th edition AJCC manual for staging
- Key cutoffs in size are 2, 5 and 10 cm
- Above grading scheme incorporates one element of staging, the tumor size
- Other relevant points should be included in report
- Wider margins of soft tissue tumors are not required
Report should include:
- Epithelioid vs. spindle morphology
- Mitotic rate
- Presence or absence of coagulative tumor necrosis
- Results of immunohistologic stains and genetic studies, if performed
- Size
- Location
- Margin status
- Any clear margin is sufficient
- Wider margins of soft tissue tumors are not required
- Organs and tissues involved
- Sites of spread
