Comparative analysis of imaging and pathology features of mucinous carcinoma of the breast

Background: The purpose of the study was to explore the relationship between the mammographic features, MR features, and pathological manifestations of PMBCs and MMBCs.

Patients and methods: Twenty-seven cases of mucinous breast carcinoma confirmed in surgical biopsy, including 18 cases of PMBC and 9 cases of MMBC, were included (mean age, 51.2 and 53.3 years, respectively). All patients underwent preoperative mammography, and 13 of 27 patients underwent preoperative MR imaging (MRI), 4 of whom underwent diffusion-weighted imaging. All mammographic and MRI information, such as the size, shape, borders of the mass, and evidence of calcification were classified according to the American Collage of Radiology (ACR) Breast Imaging-Reporting And Data System (BI-RADS) mammography/MR lexicon. The signal intensity of the mass was visually classified as low, iso, high, strongly high, or mixed in accordance with surrounding mammary gland tissues. The pattern of internal enhancement of the mass included homogeneity, rim enhancement, central enhancement, dark internal septation, and enhancing internal septation. The kinetic curve pattern was categorized into 3 types: persistent, plateau, or washout.

Results: There was no significant difference PMBC and MMBC in the shape of tumor, calcifications, T2 signal intensity, internal mass enhancement, kinetic curve assessment, and positivity for estrogen receptor (ER), progesterone receptor (PR), and human epidermalgrowth factor receptor-2 (HER-2). The PMBC tumors were larger than MMBC tumors (P < .001), and MMBC tended to present as an ill-circumscribed mass (P = .043). The ADC values of the 5 lesions of 4 mucinous breast carcinoma (MBCs) ranged from 0.771 to 2.252 × 10(3) mm(2)/s, markedly greater than that of conventional infiltrating ductal carcinoma (IDC). The ADC values of MMBC were visibly less than those of PMBC for the former mixed with massive tumor cells of IDC.

Conclusion: MBC commonly presented as masses with well circumscribed, round, or lobular shapes. The remaining cases presented with focal symmetry. The rate of regional nodal involvement of MBC was less than that of IDC. The MR features of PMBC included benign (homogenous intensity on T1-weighted imaging [WI] and T2-WI, persistent enhancement pattern) and malignant characteristics (rim or heterogeneous enhancement). The ADC values of MBC were greater than those of benign lesions and other malignant tumors. We believe that the combination of mammography and Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) may help to improve the diagnostic accuracy of MBC.