<h4>Objective</h4>To compare the diagnostic performance of non-contrast MRI versus MRI with contrast for differentiating atypical lipomatous tumors (ALT) from lipomas.<h4>Materials and methods</h4>This multicenter retrospective study included subjects with a histopathologic diagnosis of lipoma or ALT and a preoperative MRI study with contrast. This evidence concerns the gene GPT and lipoma.