Features of Phyllodes Tumours and Fibroadenomas Differ on MR Images

This retrospective study aimed to determine how the magnetic resonance imaging (MRI) and histopathological findings of phyllodes tumours (PT) and fibroadenomas (FA) correlate and verify whether they are useful for preoperative diagnosis.
We retrospectively reviewed 12 PT and 43 FA that were surgically resected after MRI assessment between 2009 and 2015. The shape and signal intensity (SI) of the tumours on T2-weighted images (T2WI), the apparent diffusion coefficient, and SI were dynamically assessed.
High SI areas suggestive of haemorrhage were significantly more frequent on pre-contrast T1WI of PT than that of FA (66.7% vs. 16.2%, p = 0.00034).
The results of the SI analysis showed a higher intratumoural SI for PT than FA on T2WI (7.07 vs. 4.37, p = 0.0022).
Overall enhancement was more intense among PT than FA, while SI was significantly higher at 100 seconds (2.03 vs. 1.60, p = 0.043) when enhanced effects on pre-enhanced tumours were quantified based on SI ratios.
Not only can MRI morphologically differentiate PT from FA, it can also provide information about tissue composition and vascularization, the quantitation of which seems useful for differentiation.