Ultrasonography and histology correlation in BI-RADS 4/5 small breast lesions among Thai patients

Background: Ultrasonography is an important imaging tool in detection of small breast cancers, particularly in younger women with dense breasts. Among the ultrasonographic characteristics for the malignancy, it is unclear which are common or more predictive. Objective: Analyze breast ultrasonograms and determine the common and predictive characteristics of the BI-RADS 4/5 small breast lesions that were correlated with histology-proved carcinoma among Thai patients. Methods: Data were collected retrospectively between November 2006 and September 2007 at King Chulalongkorn Memorial Hospital. Forty-five BI-RADS 4 or 5 small breast lesions from 41 patients were reviewed for ultrasonographic characteristics and for correlation between each of these features and histology-proved malignancy. Results: There were 15 out of 30 lesions of BI-RADS 4 and 14 out of 15 of BI-RADS 5 that were histologically proven breast carcinoma. The lesion dimension ranged from 0.27 cm to 1.5 cm (mean: 0.98 cm). The malignant signs that were common consisted of irregular shapes (70%) and posterior shadowing (35.6%). However, the most correlating signs for malignancy were vascularity of the lesion 100%, and spiculated margins 100%. The other characteristics for malignancy, in descending order, were marked hypoechoicity 88.9%, microcalcifications within mass 85.7%, echogenic halo 83.3%, shadowing 81.3%, branched pattern 77.8%, duct extension 75%, irregular shape72.2%, and taller than wide orientation 70%. Conclusion: Irregular shape and shadowing were the two most common malignant signs that characterized BI-RADS 4,5 small breast lesions by ultrasonography. However, the most predictive signs were increases in vascularity and spiculated margins.