Lipoma_vs

Features suggestive of lipoma:: Completely fatty or thin septations only.; No nodules.; Less than 10-13 cm.; Superficial subcutaneous location.; Presence of interposed muscle fibers.; None of the above are 100% specific.
2002, Radiology, Kransdorf et al.: n=40 (MR) n=29 (CT); Ground truth: pathology reports; No liposarcomas with 100% fat; But, thick septa, thin septa, nodules were absent in some liposarcomas. Specific percentages not reported.; Lipomas can be heterogenous (fat necrosis); Conclusion: "completely fatty lesions - lipomas"
2009, European Journal of Radiology, Donato et al.: Two cases of MDM2+ ALT that contained muscle fibers
2013, Skeletal Radiology, Brisson et al.: n=87; Ground truth: MDM2; MR sensitivity for ALT: 91%; Completely fatty: 4/87 all lesions (5%); Completely fatty: 4/33 ALTs (12%); Muscle fibers in 1 ALT
2019, BMC Cancer (PMC), Knebel et al.: n=113; Ground truth: MDM2; Most reliable criteria - septa >2mm. 85% sensitivity, 86% specificity; IR kappa - 0.73-0.85; ALT with thin septa: 7/113 all lesions (6%); ALT with thin septa: 7/47 ALTs (15%); ALT without contrast enhancement: 5/113 all lesions (4%); ALT without contrast enhancement: 5/47 ALTs (11%); Nodules in only 9/47 ALTs (19%)