title: Strain elastography features of epidermoid tumours in superficial soft tissue: differences from other benign soft-tissue tumours and malignant tumours.
abstract: OBJECTIVE
  We evaluated ultrasonographic features of superficial epidermoid tumour with a focus on strain elastography (SE) features that will help in the differential diagnosis of epidermoid tumour from other benign and malignant soft-tissue tumours.
  
  
  METHODS
  We retrospectively evaluated ultrasonographic and SE data of 103 surgically confirmed superficial soft-tissue tumours and tumour-like lesions: 29 cases of epidermoid tumour, 46 cases of other benign tumours and 28 cases of malignant tumour. SE and B-mode imaging were performed at the same time. SE characteristics were assigned into four grades (1-4) according to their elasticity. Interobserver agreement for the four SE scores between the two radiologists was analysed using kappa statistics. We classified each SE finding as a hard lesion (SE Score 3-4) or soft lesion (SE Score 1-2) and compared these findings using the χ(2) test to identify whether a significant difference in mass hardness existed among epidermoid tumour, other benign tumour and malignant tumour.
  
  
  RESULTS
  Overall interobserver agreement according to the four SE scores was moderate (κ = 0.540), and overall agreement for the hardness [soft (Score 1-2) or hard (Score 3-4)] was almost perfect (κ = 0.825). Malignant tumours showed higher SE scores (3-4, hard nature) than did epidermoid tumour or other benign soft-tissue tumours. There were no differences in SE score between epidermoid tumour and other benign tumours.
  
  
  CONCLUSIONS
  Superficial epidermoid tumour exhibits a softer nature than does malignant tumour but does not have a different SE pattern from other benign tumours.
  
  
  CONCLUSIONS
  SE features of epidermoid tumour might be helpful in differentiating from other benign and malignant tumours.
authors.affiliation: 1 Department of Radiology, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: H J
authors.initials: HJ
authors.lastname: Park
authors.forename: S Y
authors.initials: SY
authors.lastname: Lee
authors.forename: S M
authors.initials: SM
authors.lastname: Lee
authors.forename: W T
authors.initials: WT
authors.lastname: Kim
authors.forename: S
authors.initials: S
authors.lastname: Lee
authors.forename: K S
authors.initials: KS
authors.lastname: Ahn
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D055119:Elastic Modulus; D054459:Elasticity Imaging Techniques / Q000379:methods*; D005260:Female; D006244:Hardness; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012983:Soft Tissue Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000601:surgery
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