Multi-slice spiral computed tomography in differential diagnosis of gastric stromal tumors and benign gastric polyps, and gastric stromal tumor risk stratification assessment

Table 1 National Institutes of Health evaluation criteria for gastric stromal tumor pathological risk

GST Hazard classification	Lesion diameter (cm)	Mitosis (/50HPF)	Primary tumor location
Very low risk	< 2.0	≤ 5.0	Any position
Low risk	2.1 - 5.0	≤ 5.0	Any position
Medium risk	2.1 - 5.0	> 5.0	Stomach
	< 5.0	6.0 - 1.0	Any position
	5.0 - 10.0	≤ 5.0	Stomach
High risk	Any case	Any case	Tumor rupture
	> 10.0	Any case	Any position
	Any case	> 10.0	Any position
	> 5.0	> 5.0	Any position
	2.1 - 5.0	> 5.0	Non-stomach
	5.0 - 10.0	≤ 5.0	Non-stomach

GST: Gastric stromal tumor.