Differences in MRI findings of superficial spindle cell lipoma and atypical lipomatous tumor/well-differentiated liposarcoma

• Published in: British journal of radiology Vol. 96; no. 1143; p. 20220743
• Main Authors: Kawaguchi, Masaya, Kato, Hiroki, Kobayashi, Kazuhiro, Miyazaki, Tatsuhiko, Nagano, Akihito, Noda, Yoshifumi, Hyodo, Fuminori, Matsuo, Masayuki
• Format: Journal Article
• Language: English
• Published: England The British Institute of Radiology 01.02.2023
• Subjects: Diagnostic Radiology: Full Paper
• ISSN: 0007-1285; 1748-880X
• DOI: 10.1259/bjr.20220743

This study aimed to evaluate the efficacy of using MRI findings to differentiate superficial spindle cell lipomas (SCLs) from atypical lipomatous tumor/well-differentiated liposarcomas (ALT/WDLs). This study included 12 patients with histopathologically proven superficial SCLs and 11 with ALT/WDLs. MRI findings for both pathologies were retrospectively reviewed and compared between the two pathologies. The neck, upper back, and shoulder regions were more frequent locations of SCLs than of ALT/WDLs (100% 55%, < 0.05), whereas no significant differences were observed in age and sex. The median maximum diameter of the lesion was smaller in SCLs than in ALT/WDLs (44 mm [interquartile range (IQR): 35-63] 102 mm [IQR: 86-119], < 0.05). On weighted images, non-fatty area was more frequently observed in SCLs than in ALT/WDLs (73% 25%, < 0.05), and the median rate of non-fatty area was larger in SCLs than in ALT/WDLs (7.5% [IQR: 1.0-53] 0% [IQR: 0-0.2], < 0.05). On fat-suppressed weighted images, a solid hyperintense area was more frequently observed in SCLs than in ALT/WDLs (83% 27%, < 0.05). The maximum diameter, non-fatty area on weighted images, and solid hyperintense area on fat-suppressed weighted images were useful imaging features for differentiating superficial SCLs from ALT/WDLs. In superficial lipomatous tumors, small tumor size and non-fatty solid area were valuable findings for diagnosing SCLs.