title: Metastatic basal cell carcinoma: report of two cases and literature review.
abstract: BACKGROUND
  Metastatic basal cell carcinoma (MBCC) is defined as primary cutaneous basal cell carcinoma (BCC) that spreads to distant sites as histologically similar metastatic deposits of BCC. There are less than 300 reported cases of MBCC in the literature.
  
  
  METHODS
  This article examines two cases of MBCC and provides a literature review of risk factors inherent in epidemiology, patient demographics, and the clinicohistopathological characteristics of primary and metastatic BCC lesions.
  
  
  RESULTS
  MBCC is a rare complication of BCC with high morbidity and mortality rates. Patients with MBCC often begin with long-standing primary BCC lesions that are either large or recurrent after treatment. Cases of MBCC have a higher incidence of the more aggressive histologic patterns (morpheic, infiltrating, metatypical, and basosquamous). Perineural space invasion may be an indicator of aggressive disease. Metastases often involve regional lymph nodes, lungs, bone, and skin.
  
  
  CONCLUSIONS
  These case reports and review provide important diagnostic and management considerations for primary BCC and MBCC. Early intervention with aggressive treatment measures may improve the prognosis and survival of MBCC patients.
authors.affiliation: Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Patricia T
authors.initials: PT
authors.lastname: Ting
authors.forename: Richard
authors.initials: R
authors.lastname: Kasper
authors.forename: John P
authors.initials: JP
authors.lastname: Arlette
mesh_terms: D002280:Basal Cell Carcinoma / Q000473:pathology* / Q000628:therapy*; D005153:Facial Neoplasms / Q000473:pathology* / Q000628:therapy*; D017809:Fatal Outcome; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015580:Mohs Surgery; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local