title: Squamous Cell Carcinoma In Situ Overlying Merkel Cell Carcinoma.
abstract: BACKGROUND
  Merkel cell carcinoma (MCC) is a rare and aggressive cutaneous neoplasm that has exhibited an exponential increase in incidence in the past 3 decades. Combined MCC and cutaneous squamous cell carcinoma (SCC/MCC) is an uncommon variant of MCC that exhibits worse prognosis than pure MCC.
  
  
  OBJECTIVE
  To describe the clinical presentation, dermoscopy, and histology of an unusual subtype of combined SCC/MCC.
  
  
  RESULTS
  A 73-year-old white woman presented with an ulcerated and violaceous 10-mm plaque on her right jawline that had been present for 2 to 3 months. On dermoscopy, the lesion was predominantly milky pink to red with peripheral crusting and large-caliber polymorphous vessels. Histology revealed SCC in situ above and adjacent to MCC. The tumor was excised with clear margins, and sentinel lymph node scintography was negative for nodal involvement.
authors.affiliation: Mercer University School of Medicine, Savannah, GA, USA mcgowan_ma@med.mercer.edu.
authors.forename: Maria A
authors.initials: MA
authors.lastname: McGowan
authors.affiliation: Texas Tech University Department of Dermatology, Lubbock, TX, USA.
authors.forename: Matthew F
authors.initials: MF
authors.lastname: Helm
authors.affiliation: Texas Tech University Department of Dermatology, Lubbock, TX, USA.
authors.forename: Michelle B
authors.initials: MB
authors.lastname: Tarbox
mesh_terms: D000368:Aged; D002278:Carcinoma in Situ / Q000000981:diagnostic imaging / Q000473:pathology*; D015266:Carcinoma, Merkel Cell / Q000000981:diagnostic imaging / Q000473:pathology*; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000473:pathology*; D046169:Dermoscopy; D005153:Facial Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D005260:Female; D006801:Humans; D018193:Neoplasms, Complex and Mixed / Q000000981:diagnostic imaging / Q000473:pathology*; D012878:Skin Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*
keywords: Bowen disease; Merkel cell carcinoma; dermoscopy; squamous cell carcinoma in situ