Characteristic findings of primary perirenal angiosarcoma on chemical shift subtraction magnetic resonance imaging (CSS-MRI): A case report

A 70-year-old man with supraglottic carcinoma underwent computed tomography (CT) for staging purposes. A tumor measuring approximately 7 × 10 cm was found incidentally in the left perirenal space. The tumor showed homogeneous high signal intensity on chemical shift subtraction magnetic resonance imaging (CSS-MRI) suggesting the presence of minimal amounts of fat. Five months later, the tumor had grown to approximately 10 × 12 cm with indistinct margins. CSS-MRI showed high signal intensity in the tumor periphery only. The tumor was resected and the pathological diagnosis was angiosarcoma. Angiosarcomas are malignant endothelial vascular neoplasms that are highly invasive to their surroundings. Here we report a case of primary perirenal angiosarcoma that was difficult to differentiate from a dedifferentiated liposarcoma. On CSS-MRI, high signal intensity within a tumor may be a characteristic feature of primary perirenal angiosarcoma.