title: Carcinosarcoma of monoclonal origin arising in a dermoid cyst of ovary: a case report.
abstract: BACKGROUND
  Transformation of a cystic benign teratoma of the ovary into a "carcinosarcoma" has very rarely been reported and its histogenetic origin is still debated.
  
  
  METHODS
  A case of carcinosarcoma arising from a dermoid cyst is reported. The tumor showed cystic areas delimited by normal squamous epithelium, with transitional areas through dysplastic epithelium to "in situ" and infiltrating squamous cell carcinoma (SCC). The sarcomatous component showed compact tissue composed of round cells concentrically arranged around small vessels, spindle, and pleomorphic cells with a high nuclear-cytoplasmic ratio. Positive staining for vimentin, alpha smooth muscle actin and CD10, as well as P53 and P63, was found in the sarcomatous component and in some atypical basal cells of the squamous epithelium, which also showed the usual epithelial markers.
  
  
  CONCLUSIONS
  To the best of our knowledge, this is the first case of carcinosarcoma arising from a dermoid cyst in which a histogenetic origin from totipotent stem cells, located in the basal squamous layer, is supported by immunohistochemical findings.
authors.affiliation: Istituto di Anatomia Patologica, Facoltà di Medicina, Università degli Studi di Palermo, Italy. annaemme@hotmail.com
authors.forename: Daniela
authors.initials: D
authors.lastname: Cabibi
authors.forename: Anna
authors.initials: A
authors.lastname: Martorana
authors.forename: Francesco
authors.initials: F
authors.lastname: Cappello
authors.forename: Elisa
authors.initials: E
authors.lastname: Barresi
authors.forename: Claudio
authors.initials: C
authors.lastname: Di Gangi
authors.forename: Vito
authors.initials: V
authors.lastname: Rodolico
mesh_terms: D000368:Aged; D002296:Carcinosarcoma / Q000175:diagnosis / Q000473:pathology*; D002471:Cell Transformation, Neoplastic / Q000473:pathology*; D003884:Dermoid Cyst / Q000175:diagnosis / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D010051:Ovarian Neoplasms / Q000175:diagnosis / Q000473:pathology*