title: Oral cavity neuroendocrine carcinoma: a comparison study with cutaneous Merkel cell carcinoma and other mucosal head and neck neuroendocrine carcinomas.
abstract: OBJECTIVE
  Published cases of oral high-grade neuroendocrine carcinoma (HGNEC) variably call the tumors Merkel cell carcinoma (MCC) or small-cell/high-grade neuroendocrine carcinoma. We studied cases of cutaneous MCC and mucosal HGNEC to better distinguish them and to better define oral cases.
  
  
  METHODS
  Twelve cutaneous MCC and 14 mucosal HGNEC cases were identified. We reviewed the hematoxylin-eosin (H&E) morphology and performed immunohistochemistry for cytokeratin 20 (CK20), thyroid transcription factor 1 (TTF-1), p63, neurofilament (NF), and achaete-scute homolog 1 (MASH-1). We also performed polymerase chain reaction (PCR) for the Merkel cell polyomavirus (MCPyV).
  
  
  RESULTS
  By morphology and immunohistochemistry, MCC and HGNEC showed many differences. CK20, NF, and TTF-1 stains were the most discriminatory. MASH-1 was expressed by both MCC and HGNEC. MCPyV was present in MCC and absent in all HGNEC. The 2 oral cavity mucosal carcinomas segregated into MCC and HGNEC types, the former having the H&E nuclear morphology and classic dot-like perinuclear CK20 staining typically associated with MCC.
  
  
  CONCLUSIONS
  Oral cavity neuroendocrine carcinoma can be segregated into MCC and small-cell/HGNEC types by morphology and CK20 immunohistochemistry. MCPyV was present by PCR in cutaneous MCC but was not found in mucosal HGNEC.
authors.affiliation: Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA. jlewis@path.wustl.edu
authors.forename: James S
authors.initials: JS
authors.lastname: Lewis
authors.forename: Eric
authors.initials: E
authors.lastname: Duncavage
authors.forename: Paul W
authors.initials: PW
authors.lastname: Klonowski
mesh_terms: D051792:Basic Helix-Loop-Helix Proteins / Q000032:analysis; D015266:Carcinoma, Merkel Cell / Q000737:chemistry / Q000473:pathology* / Q000821:virology; D018278:Carcinoma, Neuroendocrine / Q000737:chemistry / Q000145:classification / Q000473:pathology*; D004279:DNA, Viral / Q000032:analysis; D006258:Head and Neck Neoplasms / Q000737:chemistry / Q000145:classification / Q000473:pathology*; D006801:Humans; D053554:Keratin-20 / Q000032:analysis; D009061:Mouth Mucosa / Q000737:chemistry / Q000473:pathology; D009062:Mouth Neoplasms / Q000737:chemistry / Q000145:classification / Q000473:pathology*; D016900:Neurofilament Proteins / Q000032:analysis; D009687:Nuclear Proteins / Q000032:analysis; D011120:Polyomavirus / Q000302:isolation & purification; D012878:Skin Neoplasms / Q000737:chemistry / Q000145:classification / Q000473:pathology* / Q000821:virology; D000074482:Thyroid Nuclear Factor 1; D015534:Trans-Activators / Q000032:analysis; D014157:Transcription Factors / Q000032:analysis; D025521:Tumor Suppressor Proteins / Q000032:analysis
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D004279:DNA, Viral; D053554:Keratin-20; D016900:Neurofilament Proteins; D009687:Nuclear Proteins; D000074482:Thyroid Nuclear Factor 1; D015534:Trans-Activators; D014157:Transcription Factors; D025521:Tumor Suppressor Proteins; C065500:ASCL1 protein, human; C000614412:NKX2-1 protein, human; C115051:TP63 protein, human