Table 1.

False-negative diagnosis after US-guided 14-gauge CNB

Patient age at CNB (years)	Characteristics on US	Size of lesion (mm)		BI-RADS category pre-core biopsy	No. of cores	Core biopsy pathology	Final diagnosis
		At initial biopsy	At surgical excision
53	Irregular, hypoechoic, posterior acoustic shadowing	11 × 10 × 8	11 × 10 × 8	4C	6	Fibrous mastopathy	Invasive ductal carcinoma
50	Subtle, hypoechoic, posterior associated shadowing	7 × 9 × 4	7 × 9 × 4	4C	4	Fragments of dense tissue with a few dilated ducts	Invasive mammary carcinoma