title: MR imaging findings of pilomatricomas: a radiological-pathological correlation.
abstract: BACKGROUND
  Magnetic resonance imaging (MRI) findings of pilomatricomas have yet to be determined.
  
  
  OBJECTIVE
  To assess the correlation between MRI and pathological findings of pilomatricomas.
  
  
  METHODS
  MR images were obtained on patients with histologically proven pilomatricomas using a 1.5-T MR scanner. The images were retrospectively reviewed for size, signal intensity compared with skeletal muscles, and enhancement patterns. Furthermore, we assessed the presence of a reticular appearance, a ring-like appearance, and peritumoral fat stranding.
  
  
  RESULTS
  We included 11 consecutive patients with 12 histologically proven pilomatricomas (3 boys/men, 8 girls/women; age range, 4-76 years; mean age, 20 years; median age, 14 years). The tumors were located in the head and neck (n = 6), upper extremities (n = 5), and lower extremities (n = 1). The maximum tumor diameter was in the range of 7-32 mm (mean, 16.5 mm). On T2-weighted (T2W) images, five tumors showed homogeneous hypointensity, whereas six showed reticular hyperintensity and one showed cystic hyperintensity. On fat-suppressed T2W images, nine tumors showed reticular hyperintensity, eight showed ring-like hyperintensity, and five showed peritumoral fat stranding. On fat-suppressed gadolinium-enhanced T1-weighted (T1W) images, one tumor showed no enhancement, whereas three showed reticular enhancement and five showed ring-like enhancement. Histologically, edematous and fibrous stroma was observed in 10 tumors, tumor capsules in 11, and inflammatory cell infiltration of the peritumoral fat tissue in nine.
  
  
  CONCLUSIONS
  MRI features of pilomatricomas included reticular and ring-like hyperintensities on fat-suppressed T2W images and reticular and ring-like enhancement on fat-suppressed gadolinium-enhanced T1W images.
authors.affiliation: Department of Radiology, Gifu University School of Medicine, Gifu, Japan hkato@gifu-u.ac.jp.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Kato
authors.affiliation: Department of Radiology, Gifu University School of Medicine, Gifu, Japan High-level Imaging Diagnosis Center, Gifu University Hospital, Gifu, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kanematsu
authors.affiliation: Department of Radiology, Gifu University School of Medicine, Gifu, Japan.
authors.forename: Haruo
authors.initials: H
authors.lastname: Watanabe
authors.affiliation: Department of Orthopedic Surgery, Gifu University School of Medicine, Gifu, Japan.
authors.forename: Akihito
authors.initials: A
authors.lastname: Nagano
authors.affiliation: Department of Dermatology, Gifu University School of Medicine, Gifu, Japan.
authors.forename: En
authors.initials: E
authors.lastname: Shu
authors.affiliation: Department of Dermatology, Gifu University School of Medicine, Gifu, Japan.
authors.forename: Mariko
authors.initials: M
authors.lastname: Seishima
authors.affiliation: Department of Pathology, Gifu University School of Medicine, Gifu, Japan.
authors.forename: Tatsuhiko
authors.initials: T
authors.lastname: Miyazaki
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005260:Female; D006201:Hair Diseases / Q000000981:diagnostic imaging* / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D018296:Pilomatrixoma / Q000000981:diagnostic imaging* / Q000473:pathology; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology
keywords: Pilomatricoma; calcifying epithelioma of Malherbe; magnetic resonance imaging (MRI)