title: Primary malignancy in giant cell tumor: a case report.
abstract: BACKGROUND
  Primary malignancy in giant cell tumor (PMGCT) is rare. It is defined as a high-grade sarcoma originating in a giant cell tumor (GCT) and seems to behave less aggressively than its secondary counterpart does.
  
  
  METHODS
  This report presents the case of a 39-year-old female with pain in her left shoulder for one month. Radiography showed a pathological fracture of the proximal humerus associated with an osteolytic lesion. Histopathological analysis showed typical areas of GCT juxtaposed with a sarcomatous component.
  
  
  CONCLUSIONS
  PMGCT seems to behave less aggressively than secondary malignancy in GCT, and it may simulate its more common benign counterpart clinically and radiographically. However, it requires a more aggressive type of treatment.
authors.affiliation: Department of Orthopedics and Traumatology, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil. zosimo_jr@yahoo.com.br
authors.forename: Rosalvo Zósimo
authors.initials: RZ
authors.lastname: Bispo Júnior
authors.forename: Olavo Pires de
authors.initials: OP
authors.lastname: Camargo
authors.forename: Cristiane Marie
authors.initials: CM
authors.lastname: Ida
authors.forename: André Mathias
authors.initials: AM
authors.lastname: Baptista
authors.forename: Marcelo Barbosa
authors.initials: MB
authors.lastname: Ribeiro
authors.forename: José Marcello
authors.initials: JM
authors.lastname: Bruno
authors.forename: Cláudia Regina Gomes Cardim Mendes de
authors.initials: CR
authors.lastname: Oliveira
mesh_terms: D000328:Adult; D001859:Bone Neoplasms / Q000473:pathology*; D005260:Female; D018212:Giant Cell Tumor of Bone / Q000473:pathology*; D006801:Humans; D009378:Neoplasms, Multiple Primary / Q000473:pathology*; D012516:Osteosarcoma / Q000473:pathology*; D011859:Radiography; D012782:Shoulder; D012784:Shoulder Fractures / Q000000981:diagnostic imaging / Q000473:pathology*