Low-grade fibromyxoid sarcoma: ultrasound and magnetic resonance findings in two cases.

Low-grade fibromyxoid sarcoma is a rare, slow-growing, yet metastasizing neoplasm characterized by histopathological fibrous/myxoid zonal alternations, which occasionally display an intralesional multinodular appearance. We report on the radiological features of two cases of low-grade fibromyxoid sarcoma. Case 1 was a large ovoid mass with a well-defined margin in the thigh, showing the characteristic multiple, intralesional variable-sized nodules on high-frequency ultrasound (US) and magnetic resonance imaging (MRI), some of the nodules showing a target-like appearance. Case 2 was a dumbbell-shaped chest wall mass showing invasive features without the intralesional multinodular appearance on MRI. The gross radiological appearances of our two cases were somewhat dissimilar, but they shared a pattern of low/high signal zonal distinction without hemorrhage or necrosis within the masses on MRI.