title: The predictive value of imaging studies in evaluating regional lymph node involvement in Merkel cell carcinoma.
abstract: BACKGROUND
  Merkel cell carcinoma (MCC) is a rare cutaneous neuroendocrine malignancy with high potential for nodal or distant metastatic spread. Little information exists on sensitivity and specificity of various imaging techniques when compared with the gold standard of histopathologic evaluation of the lymph node basin.
  
  
  OBJECTIVE
  We sought to further understand the value of various imaging modalities in the staging and initial workup of patients with MCC.
  
  
  METHODS
  Of 240 patients with primary MCC evaluated between 1981 and 2008, 99 had diagnostic imaging at initial presentation with biopsy-proven cutaneous MCC and had histopathologic nodal evaluation within 4 weeks of the initial scan. We conducted a retrospective chart review of these identified patients.
  
  
  RESULTS
  Computed tomography (n = 69) demonstrated a sensitivity of 47%, specificity of 97%, positive predictive value of 94%, and negative predictive value of 68% in detecting nodal basin involvement. Fluorine-18-fluorodeoxyglucose positron emission tomography scan (n = 33) demonstrated a sensitivity of 83%, specificity of 95%, positive predictive value of 91%, and negative predictive value of 91% in detecting nodal basin involvement. Magnetic resonance imaging (n = 10) demonstrated a sensitivity of 0%, specificity of 86%, positive predictive value of 0%, and negative predictive value of 67% in detecting nodal basin involvement.
  
  
  CONCLUSIONS
  This was a retrospective study with small sample size.
  
  
  CONCLUSIONS
  Use of fluorine-18-fluorodeoxyglucose positron emission tomography in the evaluation of a regional lymph node basin in primary MCC is significantly more sensitive and equally specific when compared with traditional computed tomography. Both fluorine-18-fluorodeoxyglucose positron emission tomography and computed tomography are more sensitive than clinical examination alone.
authors.affiliation: Division of Dermatologic Surgery, Mayo Clinic, Rochester, Minnesota 55905, USA.
authors.forename: Michael B
authors.initials: MB
authors.lastname: Colgan
authors.forename: Tina I
authors.initials: TI
authors.lastname: Tarantola
authors.forename: Amy L
authors.initials: AL
authors.lastname: Weaver
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Wiseman
authors.forename: Randall K
authors.initials: RK
authors.lastname: Roenigk
authors.forename: Jerry D
authors.initials: JD
authors.lastname: Brewer
authors.forename: Clark C
authors.initials: CC
authors.lastname: Otley
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015266:Carcinoma, Merkel Cell / Q000175:diagnosis* / Q000556:secondary*; D003952:Diagnostic Imaging; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012878:Skin Neoplasms / Q000473:pathology*