MALIGNANT BREAST TUMOURS: ROLE OF MRI IN PREDICTING HISTOPATHOLOGICAL GRADING

Abstract

Breast cancer can have a variable biological behavior and aggressiveness. The histopathological grade expresses the degree of malignancy of the tumor. Studying the relationship between the grade and MRI findings of breast cancer is essential as the histological grade affects prognosis and outcome. Dynamic contrast-enhanced MR imaging is a sensitive imaging technique for detection and diagnosis of breast cancer. Although it provides morphological and functional information about the tumor, its role in assessing prognostic factors (including grade) of breast cancer is still controversial. Diffusion weighted imaging is a fast non-invasive technique that can be easily integrated into the standard breast MRI protocol. It provides information not otherwise available about tissue cellularity, which is a main factor that determines the histological grade. Our study, as well as others, revealed the usefulness and the reliability of DWI and ADC mapping in differentiating high grade from low grade tumors. There was an inverse correlation between the ADC value and the grade. It also revealed that high grade tumors (grade III) were more associated with washout curve compared to those with lower grades (grades I and II). However, there was no significant correlation between the grade of the tumour and the pattern of enhancement or any of the morphological criteria of the tumor. That makes DWI the best non-invasive tool available to predict grades of breast carcinoma. However, further larger and more detailed studies are still needed to fully understand the role MR imaging in distinguishing different histological grades of breast cancer.

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