Abstract P4-03-09: Malignant hyperechoic lesions in breast ultrasound - Frequency and characteristics

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Abstract PURPOSE Challenge current axiom regarding hyperechogenic lesions in breast US categorized as mainly benign lesions. 2) Present frequency of malignant hyperechoic lesions, describe their sonographic and histological characteristics. METHOD AND MATERIALS IRB approved retrospective review of 2369 consecutive US-guided Core biopsies between 2006 and 2014. Lesions were considered hyperechogenic when more than 90% of its volume had higher echogenicity than surrounding subcutaneous tissue. Variables assessed were: age, size, histology, mass or non-mass, margins, echogenicity, acoustic effect, orientation, location, presence of a hypoechoic center, vascularization and BI-RADS category. Qualitative variables were described by percentage distribution, mean and SD. RESULTS Thirty one (1,3%) lesions biopsied were hyperechoic: only 17 (54.8%) were benign. We found 14 patients (range, 39-81 years, mean 57,5 years) with hyperechoic cancers, accounting for 1,77% of all cancers. 12 (85,7%) were ductal and 2 (14,3%) lobular histology (mean 17,5 mm range 8-40mm). All of them exhibited a small central hypoechoic area and were partially or completely surrounded by fatty tissue. Shape, margins, orientation and vascular architecture were highly suggestive of malignancy at US, mammography and in MRI (BI-RADS 4B and 5). On histology, all lesions were surrounded by fatty tissue, with a low–cell count collagenous center with a higher peripheral cellularity, mixing and interweaving with adipose tissue. CONCLUSION Hyperechogenic breast cancers are rare (1.77%), and we challenge the current concept of high rate of benignity with a 45,2% of chances for malignancy. We propose that hyperechogenicity is given by interweaving bundles with adipose tissue, which provide higher amount of acoustic reflective surfaces, thus explaining its sonographic pattern. CLINICAL RELEVANCE/APPLICATION Hyperechogenic breast lesions should not be considered as always benign. Malignancy thresholds should not be influenced by this sonographic characteristic. We propose histopathological explanation of this sonographic pattern. Citation Format: Camacho J, Horvath E, Pizzolon MF, Pinochet MA, Gallegos M, Galleguillos C, Uchida M, Cadiz F, Silva C. Malignant hyperechoic lesions in breast ultrasound - Frequency and characteristics. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-03-09.