title: Merkel cell carcinoma in organ-transplant recipients: report of two cases with unusual histological features and literature review.
abstract: BACKGROUND
  Non-melanoma skin cancers are the commonest malignancies after organ transplantation and are often associated with human papillomavirus (HPV). Merkel cell carcinoma is an uncommon neuroendocrine skin tumor, of which 67 cases have been reported up till now, usually briefly, in organ transplant patients.
  
  
  METHODS
  Among a cohort of 2340 organ-transplant recipients, two patients (one renal, one heart) developed cutaneous Merkel cell carcinomas 5 and 12 years of post graft, respectively. These were studied histologically and immunohistochemically, as well as virologically for the presence of HPV. A thorough literature review of all reported cases of Merkel cell carcinoma following solid organ transplantation was performed.
  
  
  RESULTS
  Despite a typical immunophenotype, the tumors showed unusual histological features: both were epidermotropic, and one was intermingled with a bowenoid squamous cell carcinoma. Search for HPV by immunohistochemistry and PCR proved negative in both cases.
  
  
  CONCLUSIONS
  In the setting of organ transplantation, Merkel cell carcinoma is much rarer than other non melanoma skin cancers but may show unusual histologic features. HPV do not seem to be involved in its pathogenesis.
authors.affiliation: Department of Dermatology/EA 37-32, University Cl. Bernard, France. kanitakis@lyon.inserm.fr
authors.forename: Jean
authors.initials: J
authors.lastname: Kanitakis
authors.forename: Sylvie
authors.initials: S
authors.lastname: Euvrard
authors.forename: Brigitte
authors.initials: B
authors.lastname: Chouvet
authors.forename: Agripina Cristina
authors.initials: AC
authors.lastname: Butnaru
authors.forename: Alain
authors.initials: A
authors.lastname: Claudy
mesh_terms: D000368:Aged; D015266:Carcinoma, Merkel Cell / Q000209:etiology* / Q000473:pathology / Q000821:virology; D006084:Graft Rejection / Q000517:prevention & control; D016027:Heart Transplantation / Q000276:immunology*; D006801:Humans; D016867:Immunocompromised Host; D007150:Immunohistochemistry; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D016030:Kidney Transplantation / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D027383:Papillomaviridae / Q000302:isolation & purification; D012878:Skin Neoplasms / Q000209:etiology* / Q000473:pathology / Q000821:virology
chemical_list: D007166:Immunosuppressive Agents