Skeletal Radiology

, Volume 36, Issue 9, pp 829–834 | Cite as

Cortico-medullary continuity in bizarre parosteal osteochondromatous proliferation mimicking osteochondroma on imaging

  • Leon D. RybakEmail author
  • Luigia Abramovici
  • Samuel Kenan
  • Martin A. Posner
  • Fiona Bonar
  • German C. Steiner
Scientific Article


Bizarre parosteal osteochondromatous proliferation (BPOP), or Nora’s lesion, is an unusual surface-based lesion of bone found most commonly in the hands and feet. In the original description of the lesion and in all publications that followed, one of the key imaging characteristics used to define this entity was the lack of cortico-medullary continuity with the underlying bone. The authors present 4 unique cases of pathologically proven BPOP in which cortico-medullary continuity with the underlying bone was demonstrated on imaging. It is believed that florid reactive periostitis, BPOP and turret osteochondroma may reflect points along the same continuum with trauma the likely inciting event. The authors suggest that, given this continuum, it may be possible to have BPOP lesions demonstrating overlapping imaging features with osteochondroma. If this is the case, strict adherence to the standard imaging criterion of lack of continuity between the lesion and the underlying bone may lead to misdiagnosis of these unusual cases of BPOP as osteochondromas.


Bizarre parosteal osteochondromatous proliferation Turret exostosis Florid reactive periostitis CT MRI 


  1. 1.
    Nora FE, Dahlin DC, Beabout JW. Bizarre parosteal osteochondromatous proliferation of the hands and feet. Am J Surg Pathol 1983; 7: 245–250.PubMedCrossRefGoogle Scholar
  2. 2.
    Dhondt E, Oudenhoven L, Khan S, et al. Nora’s lesion, a distinct radiological entity? Skelet Radiol 2006; 35: 497–502.CrossRefGoogle Scholar
  3. 3.
    Dorfman HD, Czerniak B. Bone tumors. St. Louis: Mosby; 1998.Google Scholar
  4. 4.
    Orui H, Ishikawa A, Tsuchiya T, Ogino T. Magnetic resonance imaging characteristics of bizarre parosteal osteochondromatous proliferation of the hand: a case report. J Hand Surg 2002; 27: 1104–1108.CrossRefGoogle Scholar
  5. 5.
    Meneses MF, Unni KK, Swee RG. Bizarre parosteal osteochondromatous proliferation of bone (Nora’s lesion). Am J Surg Pathol 1993; 17: 691–697.PubMedCrossRefGoogle Scholar
  6. 6.
    Yuen M, Friedman L, Orr W, Cockshott WP. Proliferative periosteal processes of phalanges: a unitary hypothesis. Skelet Radiol 1992; 21: 301–303.CrossRefGoogle Scholar
  7. 7.
    Sundaram M, Wang L, Rotman M, Howard R, Saboeiro AP. Florid reactive periostitis and bizarre parosteal osteochondromatous proliferation: pre-biopsy imaging evolution, treatment and outcome. Skelet Radiol 2001; 30: 192–198.CrossRefGoogle Scholar
  8. 8.
    Ly JQ, Bui-Mansfield LT, Taylor DC. Radiologic demonstration of temporal development of bizarre parosteal osteochondromatous proliferation. Clin Imaging 2004; 28: 216–218.PubMedCrossRefGoogle Scholar
  9. 9.
    Helliwell TR, O’Connor MA, Ritchie DA, Feldberg L, Stilwell JH, Jane MJ. Bizarre parosteal osteochondromatous proliferation with cortical invasion. Skelet Radiol 2001; 30: 282–285.CrossRefGoogle Scholar
  10. 10.
    Abramovici L, Steiner GC. Bizarre parosteal osteochondromatous proliferation (Nora’s lesion): a retrospective study of 12 cases, 2 arising in long bones. Hum Pathol 2002; 33: 1205–1210.PubMedCrossRefGoogle Scholar
  11. 11.
    Michelsen H, Abramovici L, Steiner GC, Posner MA. Bizarre parosteal osteochondromatous proliferation (Nora’s lesion) in the hand. J Hand Surg [Am] 2004; 29: 520–525.CrossRefGoogle Scholar

Copyright information

© ISS 2007

Authors and Affiliations

  • Leon D. Rybak
    • 1
    Email author
  • Luigia Abramovici
    • 2
  • Samuel Kenan
    • 3
  • Martin A. Posner
    • 4
  • Fiona Bonar
    • 5
  • German C. Steiner
    • 2
  1. 1.Department of RadiologyNYU Hospital for Joint DiseasesNew YorkUSA
  2. 2.Department of Pathology and Laboratory MedicineNYU Hospital for Joint DiseasesNew YorkUSA
  3. 3.Oncology Service, Department of OrthopedicsNYU Hospital for Joint DiseasesNew YorkUSA
  4. 4.Hand Service, Department of OrthopedicsNYU Hospital for Joint DiseasesNew YorkUSA
  5. 5.Douglass Hanly Moir PathologyNorth RydeAustralia

Personalised recommendations