Cytokeratin 20-negative Merkel cell carcinoma is infrequently associated with the Merkel cell polyomavirus.
Merkel cell carcinoma is a rare, highly aggressive cutaneous neuroendocrine carcinoma most commonly seen in sun-damaged skin. Histologically, the tumor consists of primitive round cells with fine chromatin and numerous mitoses. Immunohistochemical stains demonstrate expression of neuroendocrine markers. In addition, cytokeratin 20 (CK20) is expressed in ∼95% of cases. In 2008, Merkel cell carcinoma was shown to be associated with a virus now known as Merkel cell polyomavirus in ∼80% of cases. Prognostic and mechanistic differences between Merkel cell polyomavirus-positive and Merkel cell polyomavirus-negative Merkel cell carcinoma may exist. There has been the suggestion that CK20-negative Merkel cell carcinomas less frequently harbor Merkel cell polyomavirus, but a systematic investigation for Merkel cell polyomavirus incidence in CK20-negative Merkel cell carcinoma has not been done. To test the hypothesis that Merkel cell polyomavirus is less frequently associated with CK20-negative Merkel cell carcinoma, we investigated 13 CK20-negative Merkel cell carcinomas from the files of the Cleveland Clinic and the University of Michigan for the virus. The presence or absence of Merkel cell polyomavirus was determined by quantitative PCR performed for Large T and small T antigens, with sequencing of PCR products to confirm the presence of Merkel cell polyomavirus. Ten of these (77%) were negative for Merkel cell polyomavirus and three (23%) were positive for Merkel cell polyomavirus. Merkel cell polyomavirus is less common in CK20-negative Merkel cell carcinoma. Larger series and clinical follow-up may help to determine whether CK20-negative Merkel cell carcinoma is mechanistically and prognostically unique.
1] Department of Dermatology, The Cleveland Clinic, Cleveland, OH, USA [2] Department of Pathology, The Cleveland Clinic, Cleveland, OH, USA.
Andrew G
AG
Miner
1] Department of Pathology, University of Michigan, Ann Arbor, MI, USA [2] Department of Dermatology, University of Michigan, Ann Arbor, MI, USA.
Rajiv M
RM
Patel
Department of Pathology, The Cleveland Clinic, Cleveland, OH, USA.
Deborah A
DA
Wilson
Department of Pathology, The Cleveland Clinic, Cleveland, OH, USA.
Gary W
GW
Procop
Department of Pathology, The Cleveland Clinic, Cleveland, OH, USA.
Eugen C
EC
Minca
1] Department of Pathology, University of Michigan, Ann Arbor, MI, USA [2] Department of Dermatology, University of Michigan, Ann Arbor, MI, USA.
Douglas R
DR
Fullen
1] Department of Pathology, University of Michigan, Ann Arbor, MI, USA [2] Department of Dermatology, University of Michigan, Ann Arbor, MI, USA.
Paul W
PW
Harms
Department of Pathology, The Cleveland Clinic, Cleveland, OH, USA.
Steven D
SD
Billings
D000368:Aged; D000369:Aged, 80 and over; D015266:Carcinoma, Merkel Cell / Q000378:metabolism / Q000473:pathology* / Q000821:virology; D005260:Female; D006801:Humans; D053554:Keratin-20 / Q000378:metabolism*; D008297:Male; D059965:Merkel cell polyomavirus; D008875:Middle Aged; D027601:Polyomavirus Infections / Q000378:metabolism / Q000473:pathology* / Q000821:virology; D012878:Skin Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000821:virology; D014412:Tumor Virus Infections / Q000378:metabolism / Q000473:pathology* / Q000821:virology
D053554:Keratin-20