Use of BI-RADS-MRI descriptors for differentiation between mucinous carcinoma and fibroadenoma

Differentiation between Pure Mucinous Breast Carcinomas and Fibroadenomas with Strong High-Signal Intensity on T2-Weighted Images from Dynamic Contrast-Enhanced Magnetic Resonance Imaging

“…In a few cases, rim enhancement is detected also in benign lesions such as abscesses, inflammatory cysts, galactoceles, fat necrosis, and FA [14,22,23]. It has been hypothesized that relative hypovascularity in the center of an FA with rim enhancement is due to the presence of fibrosis or hyalinization [14]. In this study, 5 FAs with T2-SHi presenting with rim enhancement similar to that in PMBCs were found.…”

“…Rim enhancement is generally suggestive of malignancy, which correlates with more numerous microvessels at the periphery than in the center of the tumor, or necrosis or fibrosis in the center [20][21][22]. In a few cases, rim enhancement is detected also in benign lesions such as abscesses, inflammatory cysts, galactoceles, fat necrosis, and FA [14,22,23]. It has been hypothesized that relative hypovascularity in the center of an FA with rim enhancement is due to the presence of fibrosis or hyalinization [14].…”

“…The enhancement pattern in the delayed phase of MRI has been considered to be more appropriate than that in the early phase because both the majority of PMBCs and FAs showed persistent enhancement [14]. The enhancement patterns of PMBCs were associated with histopathologic features and the time of acquisition: In the early phase, the pattern depended on the proportion and spatial distribution of tumor cell clusters and mucinous components; the areas of hypercellularity with high microvessel density had remarkable enhancement, whereas areas with abundant mucinous component lack blood supply and had inappreciable enhancement [16][17][18].…”

“…The MRI descriptors described in the latest Breast Imaging Reporting and Data System (BI-RADS) MRI (5th edition) [13] were evaluated: maximum diameter; shape (round/oval, irregular); margin (circumscribed, non-circumscribed); dark internal septation (absent, present); initial enhancement increase (slow, moderate, rapid); kinetic curve pattern (persistent, plateau, washout); and delayed internal enhancement (homogeneous, heterogeneous, rim). The degree of lobulation (absent, weak, strong) and enhancing internal septation (absent, present) were evaluated according to reports regarding the differentiation of MBCs and FAs [8,14]. The extent of lobulation was classified as strong (acute angle) or weak (obtuse angle) by referring to published criteria [14,15].…”

“…The degree of lobulation (absent, weak, strong) and enhancing internal septation (absent, present) were evaluated according to reports regarding the differentiation of MBCs and FAs [8,14]. The extent of lobulation was classified as strong (acute angle) or weak (obtuse angle) by referring to published criteria [14,15]. In the process of imaging evaluation, we made a new observation: PMBCs with heterogeneous enhancement often were accompanied by local rim enhancement (more pronounced enhancement at the periphery than in the center of the local area of the tumor), whereas FAs presenting with heterogeneous enhancement had the opposite characteristic.…”