title: Late sarcoma development after curettage and bone grafting of benign bone tumors.
abstract: OBJECTIVE
  Rarely sarcomas develop in previous benign lesions, after a long term disease free interval. We report the experience on these rare cases observed at a single Institution.
  
  
  METHODS
  12 cases curetted and grafted, without radiotherapy developed sarcomas, between 1970 and 2005, 6.5-28 years from curettage (median 18, average 19). Age ranged from 13 to 55 years (median 30, average 32) at first diagnosis; tumors were located in the extremities (9 GCT, benign fibrous histiocytoma, ABC, and solitary bone cyst). Radiographic and clinic documentation, for the benign and malignant lesions, were available. Histology was available for 7 benign and all malignant lesions.
  
  
  RESULTS
  To fill cavities, autogenous bone was used in 4 cases, allograft in 2, allograft and tricalcium-phosphate/hydroxyapatite in 1, autogenous/allograft in 1, heterogenous in 1. For 3 cases the origin was not reported. Secondary sarcomas, all high grade, were 8 osteosarcoma, 3 malignant fibrous histiocytoma, and 1 fibrosarcoma.
  
  
  CONCLUSIONS
  Recurrences with progression from benign tumors are possible, but the very long intervals here reported suggest a different cancerogenesis for these sarcomas. This condition is extremely rare accounting for only 0.26% of all malignant bone sarcomas treated in the years 1970-2005 and represents only 8.76% of all secondary bone sarcomas treated in the same years. This incidence is the same as that of sarcomas arising on fibrous dysplasia, and is lower than those arising on bone infarcts or on Paget's disease. This possible event must be considered during follow-up of benign lesions.
authors.affiliation: Bone Tumor Center, Istituto Ortopedico Rizzoli, Bologna, Italy. piero.picci@ior.it
authors.forename: Piero
authors.initials: P
authors.lastname: Picci
authors.forename: Gabriela
authors.initials: G
authors.lastname: Sieberova
authors.forename: Marco
authors.initials: M
authors.lastname: Alberghini
authors.forename: Alba
authors.initials: A
authors.lastname: Balladelli
authors.forename: Daniel
authors.initials: D
authors.lastname: Vanel
authors.forename: Pancras C W
authors.initials: PC
authors.lastname: Hogendoorn
authors.forename: Mario
authors.initials: M
authors.lastname: Mercuri
mesh_terms: D000293:Adolescent; D000328:Adult; D001859:Bone Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D016025:Bone Transplantation; D003475:Curettage; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging / Q000601:surgery; D016609:Neoplasms, Second Primary / Q000000981:diagnostic imaging* / Q000601:surgery*; D011859:Radiography; D012509:Sarcoma / Q000000981:diagnostic imaging* / Q000601:surgery*; D016896:Treatment Outcome; D055815:Young Adult