title: Pilomatrix carcinoma: 13 new cases and review of the literature with emphasis on predictors of metastasis.
abstract: BACKGROUND
  Pilomatrix carcinoma is a rare cutaneous tumor derived from follicular matrix cells with few cases documented in the literature.
  
  
  OBJECTIVE
  We sought to better characterize this tumor by analyzing its epidemiologic, clinical, and histopathologic features in 13 new cases and by reviewing the literature.
  
  
  METHODS
  All cases of pilomatrix carcinoma from a large regional dermatopathology practice were identified and analyzed by chart review for clinical and histopathologic characteristics. Similar characteristics were compiled from an additional 123 cases in the English-language literature. Cox proportional hazards regression models were used to determine risk factors associated with the development of metastasis for all identified metastatic tumors.
  
  
  RESULTS
  Our 13 tumors were most common in middle-aged to older white men and presented mostly on the head/neck. Histopathologically, tumors were asymmetric, were poorly circumscribed, were composed of basaloid and "ghost" cells, had frequent atypical mitoses, and had infrequent lymphovascular invasion. Wide excision was considered the most definitive treatment modality, but local recurrence was common. When analyzing all reported cases of metastasis using statistics, metastasis was significantly associated (hazard ratio 3.45, P < .0413) with local tumor recurrence.
  
  
  CONCLUSIONS
  The retrospective, single-center design and the reliance on electronic medical records are limitations.
  
  
  CONCLUSIONS
  This study helps better characterize pilomatrix carcinoma and identifies potential predictors of metastasis.
authors.affiliation: Department of Dermatology, University of Alabama at Birmingham, Birmingham, Alabama. Electronic address: dr.jenniferherrmann@gmail.com.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Herrmann
authors.affiliation: Lake Erie College of Osteopathic Medicine, Bradenton, Florida.
authors.forename: Adam
authors.initials: A
authors.lastname: Allan
authors.affiliation: Georgetown University School of Medicine, Washington, District of Columbia.
authors.forename: Kara M
authors.initials: KM
authors.lastname: Trapp
authors.affiliation: Dermatology, Michigan State University College of Osteopathic Medicine, East Lansing, Michigan; Pathology, University of South Florida Morsani College of Medicine, Tampa, Florida; and Dermpath Diagnostics in Tampa, Pensacola, and Marietta, Georgia.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Morgan
mesh_terms: D000368:Aged; D005260:Female; D006201:Hair Diseases / Q000473:pathology*; D006258:Head and Neck Neoplasms / Q000473:pathology*; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology; D018296:Pilomatrixoma / Q000473:pathology*; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D012878:Skin Neoplasms / Q000473:pathology*
keywords: calcifying epitheliocarcinoma of Malherbe; malignant pilomatricoma; matrical carcinoma; metastatic pilomatricoma; pilomatrical carcinoma; pilomatrix carcinoma