Non-mass-like lesions on breast ultrasound: classification and correlation with histology

Owing to advances in ultrasound (US) technology, optimal US techniques with a high-frequency transducer can identify more and more breast lesions. However, some lesions show up as non-mass-like lesions, which are difficult to be correctly identified and often result in missed diagnosis and misdiagnosis. The purpose of the present study was to develop a classification of the US features of non-mass-like breast lesions correlated with pathology, so as to improve the diagnostic accuracy of US in non-mass-like breast lesions.

A total of 854 breast lesions in 836 consecutive women scheduled for US-guided core-needle biopsy or US-guided vacuum-assisted biopsy between May 2008 and October 2011 were initially included in this study. Finally, 80 breast lesions in 78 women were classified as non-mass-like lesion and included in this study. The US features of the 80 non-mass-like breast lesions were classified and their correlation with pathology was analysed.

Of the 80 non-mass-like breast lesions, 43 cases (53.8 %) were malignant and 37 cases (46.2 %) were benign. Fifty-two cases (73.7 %) appeared as a hypoechoic area, 22 cases (21.1 %) appeared as a hypoechoic area with sporadic or clustered microcalcification, four cases appeared as architectural distortion, and two cases appeared as solid echogenicity within a duct. The diagnostic accuracy, sensitivity, specificity, positive predictive value and negative predictive value of US for non-mass-like breast lesions were 71.25, 95.35, 43.24, 66.13 and 88.89 %, respectively. The finding of a hypoechoic area with microcalcification showed a statistically significant association with malignant lesions and its positive predictive value for carcinoma was 78.26 %.

Non-mass-like breast lesions usually appeared as a hypoechoic area or a hypoechoic area with microcalcification. The finding of a hypoechoic area with microcalcification had a close correlation with malignant lesions. US had a high sensitivity but a low specificity in the diagnosis of non-mass-like breast lesions and a definitive diagnosis requires a US-guided biopsy.