Role of multi-parametric MRI in the differentiation between mucinous breast carcinoma and fibroadenoma

Abstract

Abstract Background The purpose of this study was to evaluate diagnostic performance of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and functional MRI (diffusion and MR spectroscopy) using the latest MRI breast imaging reporting and data system (MRI-BIRADS) descriptors and non-BIRADS items for differentiation of mucinous breast carcinomas from fibroadenomas. Methods We included 19 cases of mucinous breast carcinoma and 37 cases of fibroadenoma. DCE-MRI, Diffusion-weighted MR imaging (DWI) and multi-voxel MR spectroscopy (MRS) were done, MRI-BIRADS (5th edition) analysis of the lesions was performed, and histopathological examination of all cases was done. Results According to univariate analysis, mucinous carcinoma was frequently detected in older age-group (COR = 1.4, 95% CI = 1.1–1.7 and p value < 0.001) and had more frequent irregular borders and non-circumscribed margins than fibroadenoma (COR = 11.6, 95% CI = 2–66.4 and p value = 0.002). All mucinous carcinoma had high T2 signal. Fibroadenomas had more frequent homogenous enhancement than mucinous carcinoma; none of the fibroadenomas had rim enhancement nor enhancing internal septations; mucinous carcinoma had more frequent rim enhancement and (n = 6, p value < 0.001) and enhancing internal septations (n = 7, p value < 0.001). Fibroadenoma had frequent dark non-enhancing internal septations than mucinous carcinoma (p value < 0.001). On multivariate analysis, mucinous carcinoma had significant combination of being common in older age, larger in size, with irregular shape, and non-circumscribed margins. On ADC map and MRS, mucinous carcinoma had higher ADC values and higher CHO.SNR than fibroadenoma. The mean ADC value of mucinous carcinoma was 1.3 ± 0.1 × 10−3mm2/s, which was significantly higher than that of fibroadenoma (1.1 ± 0.1 × 10−3mm2/s), with p = 0.002. Also, the mean CHO.SNR was significantly higher in mucinous carcinoma (3.1 ± 0.8) than fibroadenoma (0.8 ± 0.5) with p value < 0.001. According to our results, the presence of type 3 (washout curve), dark internal septations, non-circumscribed margins and irregular shape of the lesion showed the highest sensitivity and accuracy for differentiation of mucinous carcinomas and fibroadenomas (100, 78.6%), (89.4, 82%), (86.5, 80.3%) and (81, 71.4%), respectively. Conclusion The combined use of DCE-MRI, DW-MRI and MRS with breast MRI-BIRADS descriptors and non-BIRADS items increases the diagnostic accuracy for differentiation of mucinous carcinomas from fibroadenomas.

Keywords

• Breast MRI
• Fibroadenoma
• Mucinous carcinoma
• Diffusion
• MR spectroscopy