title: The common ultrasonographic features of pilomatricoma.
abstract: OBJECTIVE
  The purpose of this series was to describe typical ultrasonographic features of 20 cases of pilomatricoma and to improve its diagnostic rate with the use of an ultrasonographic approach.
  
  
  METHODS
  For 20 pilomatricomas in 19 patients with preoperative ultrasonography from 1995 to 2004, we reviewed age, sex, symptoms, duration, referring clinician, and tumor sites. The ultrasonographic findings were retrospectively analyzed for tumor location, shape, size, margin, echo texture, echogenicity, presence, amount, and shape of calcification, presence of a hypoechoic rim, and Doppler flow pattern.
  
  
  RESULTS
  The mean age of the 19 patients was 6.9 years (range, 1-21 years), and the female-male ratio was 1.1:1. Patients had a painful palpable mass in 10 cases (50%). Nine lesions occurred in the neck, 5 in the cheek, 2 in the preauricular region, and 4 in the extremity. All tumors were located in the subcutaneous layer. The mean size of the tumors was 13.4 mm. Fourteen pilomatricomas (70%) appeared as well-defined oval masses. Tumors were heterogeneously hyperechoic in 80% of cases. All tumors had internal echogenic foci. A hypoechoic rim was seen in 17 cases (85%). Doppler flow signals were observed in the peripheral region in 14 cases (70%). A correct preoperative diagnosis was made in 33% on the basis of clinical findings and in 76% by ultrasonography.
  
  
  CONCLUSIONS
  Diagnosis of pilomatricoma should be considered when a well-defined mass with inner echogenic foci and a peripheral hypoechoic rim or a completely echogenic mass with strong posterior acoustic shadowing in the subcutaneous layer of the head, neck, or extremity is found on ultrasonography.
authors.affiliation: Department of Radiology and Medical Research Institute, Ewha Womans University College of Medicine, 911-1 Mokdong, Yangcheongu, 158-710 Seoul, Korea.
authors.forename: Ji Young
authors.initials: JY
authors.lastname: Hwang
authors.forename: Sun Wha
authors.initials: SW
authors.lastname: Lee
authors.forename: Sang Min
authors.initials: SM
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D002114:Calcinosis / Q000000981:diagnostic imaging* / Q000473:pathology; D002277:Carcinoma / Q000000981:diagnostic imaging / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006201:Hair Diseases / Q000000981:diagnostic imaging* / Q000473:pathology; D018859:Hair Follicle / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D007223:Infant; D008297:Male; D018296:Pilomatrixoma / Q000000981:diagnostic imaging* / Q000473:pathology; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D014463:Ultrasonography / Q000379:methods / Q000592:standards