MR Imaging of Lipoma and Liposarcoma

• Published in: Acta radiologica (1987) 1999, Vol.40 (1), p.64-68
• Main Authors: Einarsdottir, H., Söderlund, V., Larson, O., Jenner, G., Bauer, H. C. F.
• Format: Article
• Language: English
• Subjects: Adipose Tissue - pathology; Adult; Aged; Biological and medical sciences; Diagnosis, Differential; Female; Humans; Investigative techniques, diagnostic techniques (general aspects); Lipoma - diagnosis; Liposarcoma - diagnosis; Male; Medical sciences; Medicin och hälsovetenskap; Middle Aged; Neoplasm Invasiveness; Osteoarticular system. Muscles; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Retrospective Studies; Soft Tissue Neoplasms - diagnosis
• ISSN: 0284-1851; 1600-0455
• DOI: 10.1080/02841859909174405

Purpose: To evaluate whether lipoma, atypical lipomatous tumors, and lipo-sarcomas can be differentiated by MR images. Material and Methods: The MR images of 59 lipomatous lesions and liposarcomas were retrospectively reviewed. Apart from size, surgical site, location and margins, the percentage of fat of the tumor volume was assessed as none, 1-75%, 75-95%, or 95-100%. Results: None of the 18 liposarcomas contained fat that could be recognized by MR imaging. The 3 atypical lipomatous tumors all contained fat but less than 75% of the tumor volume. In 32 of 38 ordinary lipomas, the percentage of fat was 95-100%, and in 4 less than 95% of the tumor volume. Two lipomas did not contain fat that could be recognized by MR imaging. Conclusion: A lesion which predominantly has a fat signal is, in all probability, an ordinary lipoma. Lesions with less fat, but still mostly fatty, may either be lipoma or atypical lipomatous tumor. In this group, the discrimination between these two entities cannot be based upon imaging features. In the absence of a fat signal, liposarcoma or lipoma cannot be differentiated from other soft tissue tumors.