RE: Distinguishing between Renal Cell Carcinoma and Fat Poor Angiomyolipoma in Diffusion-Weighted Imaging

We have read with interest the article of Ding et al. (1), entitled “Comparison of biexponential and monoexponential model of diffusion-weighted imaging for distinguishing between common renal cell carcinoma and fat poor angiomyolipoma”, which was published in the Nov-Dec. 2016 issue of the journal. The study provides useful information. However, we would like to add a few comments. Angiomyolipoma (AML), the most common tumor of mesenchymal origin, is characterised morphologically by abnormal vessels, smooth muscle cells and fatty tissue (1). It is considered as neoplasia based on the metastatic potential of some epithelioid type AMLs. Most epithelioid type AMLs are benign; but lesions with hypercellularity, atypia, and necrosis, are considered as potentially malignant Letter to the Editor