Our Radiological Experience on B3 Lesions: Correlation Between Mammographic and MRI Findings With Histologic Definitive Result

Introduction: The purpose of this study was to evaluate mammographic and magnetic resonance imaging (MRI) features in B3 lesions. Patients and Methods: From 2011 to 2018, 139 patients with histologically proven B3 lesions who underwent mammography or/and MRI, were retrospectively reviewed. B3 lesions were classified in: atypical ductal hyperplasia (ADH), lobular neoplasia (LN), papillary lesion (PL), radial scar (RS), flat epithelial atypia (FEA), phyllodes tumor (PT), or mesenchymal lesion. Imaging features evaluated were: the presence of microcalcifications, mass and architectural distortions on mammograms and type of margins (circumscribed, irregular, spiculate), enhancement (mass-like, non-mass-like), size (≤ 15 mm, > 15 mm), and kinetics curves (I, II, III) on MRI. The definitive histologic results confirmed benign lesion or were upgraded to malignancy, and the positive predictive value was calculated. Results: Histologic classification of B3 lesions counted 45 (32.37%) ADH, 12 (8.63%) LN, 25 (17.99%) PL, 5 (3.61%) RS, 31 (22.31%) FEA, 20 (14.39%) PT, and 1 (0.70%) mesenchymal lesion. One hundred seven patients had mammography, and 38 had MRI. In 90 (65%) cases, the histologic diagnosis confirmed B3, in 15 (11%) cases, benign lesion, and in 34 (24%) cases, malignancies were found, with best positive predictive value for mesenchymal tumor (1), ADH (0.36), and FEA (0.4). Significant correlations comparing core needle biopsy groups and microcalcifications (P = .016) and presence of mass (P = .002) and comparing definitive histology with the presence of mass (P = .023), were found. Regarding MRI, the morphology correlated with core needle biopsy groups (P = .038); morphology (P = .024), dimension (P = .040), and kinetic curve (P = .005) correlated with malignancy. Conclusions: The B3 category includes different entities, with various risk of malignancy; their heterogeneity is associated with specific mammographic and MRI features, although further confirmations are needed. © 2019 Elsevier Inc. Lesions suspected for breast cancer are always sampled by biopsy before management decisions are made. The result is classified basing on histologic characteristics, ranging from B1 to B5. The B3 class represents benign lesions with a possible, but not always predictable, risk of increased malignancy. Currently, every single B3 case has to be discussed in a multi-disciplinary team. Specific mammography and magnetic resonance findings can reduce the rate of surgeries on benign lesions and better evaluate the malignancy rate of B3 lesions. © 2019 Elsevier Inc.