Table 2. Relationship between ultrasound BI-RADS category and pathology in mammographically negative patients with nipple discharge.

	Pathology No. (%)		p-value*	p-value†
	Benign (n=59)	Malignant (n=8)
BI-RADS category			0.040	0.004
3	14 (100.0)	0
4A	42 (87.5)	6 (12.5)
4B	3 (75.0)	1 (25.0)
5	0	1 (100.0)

BI-RADS=Breast Imaging Reporting and Data System.

^*Fisher exact test, Mann-Whitney U-test; ^†Cochran-Mantel-Haenszel test.