Unveiling the swirl sign: A radiologic-pathologic correlation in deep angiomyxoma

Deep angiomyxoma (DA) is a rare, slow-growing soft tissue tumor typically affecting women of reproductive age. Despite its benign histology, it poses significant clinical challenges due to local invasiveness and high recurrence. Accurate diagnosis through radiologic imaging, particularly MRI, is essential for guiding treatment. One key imaging feature of DA is the “swirl sign,” a distinctive pattern on T2-weighted images. However, its histological basis remains unclear. Here, we present a case of DA in a 46-year-old woman, highlighting the correlation between radiologic and histopathologic findings. MRI showed the characteristic swirl sign, which histologically corresponded to straight-running blood vessels aligned with the tumor's long axis, supported by collagen fibers within an edematous stroma. This case offers novel insight into the origins of the swirl sign and provides research questions on this sign. Further research is needed to explore its potential as a biomarker for tumor growth and aggressiveness.