Is it possible to differentiate gastric GISTs from gastric leiomyomas by EUS?

Table 1 Proposed approach for defining the risk of aggressive behavior in GISTs

	Size (cm)	Mitotic count
Very low risk	< 2	< 5/50 HPF
Low risk	2-5	< 5/50 HPF
Intermediate risk	< 5	6-10/50 HPF
	5-10	< 5/50 HPF
High risk	> 5	> 5/50 HPF
	> 10	Any mitotic rate
	Any size	> 10/50 HPF

HPF: High-power field.

Table 2 Baseline characteristics and EUS features of the patients with leiomyomas and GISTs of the stomach n (%)

Variables	Leiomyomas (n = 7)	GISTs (n = 46)	P-value
Gender			0.686
Male	2 (28.6)	20 (43.5)
Female	5 (71.4)	26 (56.5)
Age (yr, mean ± SD)	52.6 ± 13.5	57.5 ± 8.4	0.193
Location			0.272
Upper	6 (85.7)	29 (63.0)
Middle	0 (0)	13 (28.3)
Lower	1 (14.3)	4 (8.7)
Originating layer			0.644
Second layer	0	1 (2.2)
Third layer	2 (28.6)	7 (15.2)
Fourth layer	5 (71.4)	38 (82.6)
Size (cm, mean ± SD)	3.6 ± 2.6	3.5 ± 2.3	0.967
Ulcer			0.172
Absent	7 (100)	31 (67.4)
Present	0 (0)	15 (32.6)
Growth			0.660
In	6 (85.7)	33 (71.7)
Out	1 (14.3)	13 (28.3)
Border			0.082
Regular	7 (100)	29 (63.0)
Irregular	0 (0)	17 (37.0)
Lobulation			0.426
Absent	5 (71.4)	23 (50.0)
Present	2 (28.6)	23 (50.0)
Marginal halo			0.002
Absent	6 (85.7)	10 (21.7)
Present	1 (14.3)	36 (78.3)
Echogenicity in comparison with the surrounding muscle echo			0.004
Isoechoic	7 (100)	19 (41.3)
Hyperechoic	0 (0)	27 (58.7)
Homogeneity			0.001
Homogenous	6 (85.7)	9 (19.6)
Inhomogenous	1 (14.3)	37 (80.4)
Cystic change			0.661
Absent	6 (85.7)	31 (67.4)
Present	1 (14.3)	15 (32.6)
Hyperechogenic spots			0.012
Absent	4 (57.1)	5 (10.9)
Present	3 (42.9)	41 (89.1)
Calcification			1.000
Absent	6 (85.7)	39 (84.8)
Present	1 (14.3)	7 (15.2)

Table 3 Sensitivity, specificity and positive and negative predictive values of the EUS features that differentiate GISTs from leiomyomas in the stomach (%)

EUS features	Sensitivity	Specificity	Positive predictive value	Negative predictive value
Echogenicity in comparison with the surrounding muscle echo	58.7	100	100	26.9
Homogeneity	80.4	85.7	97.4	40.0
Echogenic foci	89.1	57.1	93.2	44.4
Marginal halo	78.3	85.7	97.3	37.5
Of the above 4 features
≥ 1	97.8	57.1	93.8	80.0
≥ 2	89.1	85.7	97.6	54.5
≥ 3	84.8	85.7	97.5	46.2
All	34.8	100	100	18.9

Values are expressed as percentages.

Table 4 Univariate analysis of EUS features between benign and malignant GISTs of the stomach n (%)

Variables	Benign GIST (n = 33)	Malignant GIST (n = 13)	P-value
Size (cm, mean ± SD)	2.5 ± 1.0	6.0 ± 2.7	0.001
Ulcer			0.299
Absent	24 (72.7)	7 (53.8)
Present	9 (27.3)	6 (46.2)
Growth			0.145
In	26 (78.8)	7 (53.8)
Out	7 (21.2)	6 (46.2)
Border			0.044
Regular	24 (72.7)	5 (38.5)
Irregular	9 (27.3)	8 (61.5)
Lobulation			0.743
Absent	17 (51.5)	6 (46.2)
Present	16 (48.5)	7 (53.8)
Marginal halo			0.240
Absent	9 (27.3)	1 (7.7)
Present	24 (72.7)	12 (92.3)
Echogenicity in comparison with the surrounding muscle echo			0.115
Isoechoic	16 (48.5)	3 (23.1)
Hyperechoic	17 (51.5)	10 (76.9)
Homogeneity			0.199
Homogenous	8 (24.2)	1 (7.7)
Inhomogenous	25 (75.8)	12 (92.3)
Cystic changes			0.082
Absent	25 (75.8)	6 (46.2)
Present	8 (24.2)	7 (53.8)
Hyperechogenic spots			1.000
Absent	4 (12.1)	1 (7.7)
Present	29 (87.9)	12 (92.3)
Calcification			0.385
Absent	29 (87.9)	10 (76.9)
Present	4 (12.1)	3 (23.1)

Table 5 Multivariate analysis of EUS features between benign and malignant GISTs of the stomach

Variables	Odds ratio (95% CI)	P value
Size	9.3 (1.6-53.6)	0.013
Growth	8.7 (0.6-119.8)	0.105
Border	2.3 (0.2-22.7)	0.490
Homogenicity	2.2 (0.1-48.0)	0.606
Cystic change	1.4 (0.1-19.5)	0.800