Objective: To evaluate the relationship between magnetic resonance imaging (MRI) findings and histopathologic findings, including histologic type, histologic grade, extensive intraductal component (EIC), estrogen receptor (ER), progesterone receptor (PR), Ki-67, P53, and molecular subtypes in breast cancer.

Materials and Methods: The present data was a retrospective review of the patients that underwent breast MRI at King Chulalongkorn Memorial Hospital between January 1, 2014 and December 31, 2016. MRI was assessed for shape, margin, and internal enhancement of the mass lesion, distribution and internal enhancement of the non-mass enhancement lesions, and kinetic curve type and restricted diffusion of both mass and non-mass enhancement lesions. The association between MRI findings and histologic type, histologic grade, EIC, ER, PR, human epidermal growth factor receptor 2 (HER2), Ki-67, P53, and molecular subtypes were evaluated.

Results: One hundred seven patients with invasive breast cancers were included in the present study with 99 mass lesions and 8 non-mass enhancement lesions. Rim enhancement of the mass was a significant independent predictor of grade III (high) histologic grade (p=0.001, odd ratio 4.552), negative ER (p=0.001, odd ratio 4.644), negative PR (p=0.021, odd ratio 2.679), and positive Ki-67 status (p=0.022, odd ratio 3.373). Internal enhancement was significantly associated with molecular subtypes such as luminal A subtype appearing as heterogeneous enhancement for 78.3%, HER2-overexpressed and triple negative subtypes dominantly presented with rim enhancement for 76.9% and 75%, respectively. The authors found that spiculated tumor margin of the mass was significantly associated with negative EIC (p=0.006). Restricted diffusion of all lesions was also a significant independent predictor of negative EIC (p=0.022, odd ratio 7.417) and Ki-67 positive (p=0.028, odd ratio 7.182).

Conclusion: The consistency of the association between rim enhancement and high histologic grade, negative ER/PR, positive Ki-67 statuses in the present study may help to determine that rim enhancement was likely to predict poor pathologic prognosis of breast cancer. Rim enhancement may also predict poor molecular subtypes including HER2-overexpressed and triple negative subtypes. These results suggest that rim enhancement is the most useful MRI finding to predict histopathology and molecular subtypes of breast cancer.

Keywords: MRI, Breast cancer, Histopathology, Grade, ER, PR, HER2, Ki-67, EIC, Molecular subtypes

Received 5 Apr 2019 | Revised 19 Jun 2019 | Accepted 20 Jun 2020