Ultrasound for diagnosis of soft-tissue lipoma : accuracy and differentiating features from other soft-tissue mass
Keywords:
lipoma, ultrasound, accuracyAbstract
Objectives : To evaluate diagnostic accuracy of ultrasound for diagnosis of soft-tissue lipoma and to figure out sonographic features differentiating lipoma from other soft-tissue mass
Materials and methods : Sixty-nine masses were retrospectively reviewed. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of ultrasound diagnosis for lipoma were determined using histologic diagnosis as the reference standard. Sonographic features were compared
between lipoma and non-lipoma group. Lipomas were subdivided into superficial vs deep-seated location and small vs large size, then subgroup analysis was performed.
Results : The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of ultrasound diagnoses for lipoma were 84.85%, 91.67%, 90.32%, 86.84%, and 88.41%, respectively. Sonographic characteristics which were significantly different between lipoma and non-lipoma group include echogenicity, cystic portion, and internal vascularity. Most lipomas appeared as well-defined masses with iso- or hyperechogenicity relatively to subcutaneous fat tissue with absent cystic portion and absent internal vascularity. Accuracy of ultrasound for diagnosis of deep-seated lipoma was lower than its superficial counterpart. One large lipoma was missed by ultrasound and was further evaluated by MRI.
Conclusion : Ultrasound demonstrates good accuracy in the diagnosis of superficial soft-tissue lipoma. Iso- or hyperechogenicity with absent cystic portion and absent internal vascularity are significant sonographic features. Further investigation may be needed in deep-seated or large masses.
References
2. Fletcher CDM, Unni KK, Mertens F, editors. World Health OrganizationClassification of Tumours. Pathology and Genetics of Tumours of Soft Tissueand Bone. IARC Press: Lyon; 2002.
3. Zoga AC, Weissman BN, Kransdorf MJ, Adler R, Appel M, Bancroft LW, et al. ACR Appropriateness Criteria Soft-Tissue Masses. American college of Radiology. [serial online]2012 [cited 2017 April 25] Available from URL : https://acsearch.acr.org/ docs/69434/Narrative/.
4. Wagner JM, Lee KS, Rosas H, Kliewer MA. Accuracy of sonographic diagnosis of superficial masses. J Ultrasound Med 2013; 32:1443–50.
5. Cheng JW, Tang SFT, Yu TY, Chou SW, Wong AMK, Tsai WC.Sonographic features of soft tissue tumors in the hand and forearm. Chang Gung Med J 2007; 30(6):547-54.
6. Paunipagar BK, Griffith JF, Rasalkar DD, Chow LTC, Kumta SM, Ahuja A. Ultrasound features of deep-seated lipomas. Insights Imaging 2010;
1:149–153.
7. Ahuja AT, King AD, Kew J, King W, Metreweli C. Head and neck lipomas: sonographic appearance. Am J Neuroradiol 1998; 19:505–8.
8. Inampudi P, Jacobson JA, Fessell DP, Carlos RC, Patel SV, Sathy LO, et al. Soft-tissue lipomas: accuracy of sonography in diagnosis with pathologic correlation. Radiology 2004; 233:763-7.
9. Fornage BD, Tassin GB.Sonographic appearances of superficial soft tissue lipomas. J Clin Ultrasound 1991;19(4):215-20.
10. Shin YS, Kim YJ, Park IS, Chu YC, Kim JH, Lee HY, et al. Sonographic differentiation between angiolipomas and superficial lipomas.J Ultrasound Med 2016; 35(11):2421-9.
11. Nagano S, Yokouchi M, Setoguchi T, Ishidou Y, Sasaki H,Shimada H,et al. Differentiation of lipoma and atypical lipomatous tumor by a scoring system: implication of increased vascularity on pathogenesis of liposarcoma. BMC Musculoskeletal Disorders 2015; 16:36:1-7
12. Kuwano Y, Ishizaki K, Watanabe R, Nanko H. Efficacy of diagnostic ultrasonography of lipomas, epidermal cysts, and ganglions. Arch Dermatol 2009; 145(7):761-4.
13. Hung EHY, Griffith JF, Hung Ng AW, Lee RKL, Lau DTY, Leung JCS. Ultrasound of musculoskeletal soft-tissue tumors superficial to the investing fascia. AJR 2014; 202:W532-40.
14. Myhre JO.A consecutive 7-year series of 1331 benign soft tissue tumours. Clinicopathologic data. Comparison with sarcomas.Acta Orthop Scand 1981;52(3):287-93.
15. Gielen J, Ceulemans R, Holsbeeck, M.Ultrasound of Soft Tissue Tumors. In: SchepperAMD, Vanhoenacker F, Gielen J, Parizel PM, editors. Imaging of Soft Tissue Tumors: Springer Berlin Heidelberg; 2006. p3-18.
16. Chung HW, Cho KH. Ultrasonography of soft tissue“oops lesions”. Ultrasonography 2015; 34:217-225.
17. Rowbotham E,Bhuva S, Gupta H,Robinson P. Assessment of referrals into the soft tissue sarcoma service: evaluation of imaging early in the pathway process. Sarcoma 2012; 2012:1-5.
18. Grimer RJ.Size matters for sarcomas!. Ann R Coll Surg Engl2006;88(6):519-24.
