Osteochondroma

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Osteochondroma is a common benign chondro-osseous tumour.[1]

Exostosis[2] redirects here.

General

  • Benign.
  • Very common.[1]
  • Abnormal outgrowth of bone and cartilage - associated with growth plate.
  • Usually present before age 20.[3]
  • May be multiple and hereditary.[2]

Gross

Features:

  • Metasphyseal lesions.[4]
    • Often distal femur, proximal humerus or proximal tibia.[3]
    • Occasionally iliac mass.[5]
  • Mushroom-like shape - with broad or narrow base.

Note:

  • Very unusual in craniofacial bones.[3]

Microscopic

Features:[3]

  • Bone - forms base of "mushroom".
  • Cartilage - layer usu. thinner in older individuals.
    • Lobular arrangement[6] - clusters of 3-12 lacunae (separated by stroma).
    • May have mild atypia.
    • Nuclear enlargement - up to 5x normal.
  • Perichondrium - covers the cartilage.
    • Thin layer of cells - higher cellular density than cartilage.
      • Bland spindle cells in a fibrous (eosinophilic) stroma.

Notes:

  • Benign cartilage - one chondrocyte per lacuna, small and round nucleus, no binucleation.
  • Heterotopic ossification - no cartilage, away from joint.

DDx:

Images

www:

See also

References

  1. 1.0 1.1 Rogozhin, DV.; Bulycheva, IV.; Kushlinsky, NE.; Konovalov, DM.; Talalaev, AG.; Roshchin, VY.; Ektova, AP.; Kushnir, BL. et al. "[Osteochondroma in children and adolescents].". Arkh Patol 77 (3): 37-40. PMID 26226780.
  2. 2.0 2.1 Ohkuma, R.; McCarthy, EF.; Deune, EG. (Jun 2011). "Hereditary multiple exostoses in the hands and fingers: early presentation and early surgical treatment in family members. Case reports.". Hand (N Y) 6 (2): 209-16. doi:10.1007/s11552-010-9307-3. PMID 22654707.
  3. 3.0 3.1 3.2 3.3 Parkin, B.; Bennett, JC.; Zaher, A. (Aug 2003). "Pathologic quiz case: an iliac mass in a 25-year-old woman. Osteochondroma.". Arch Pathol Lab Med 127 (8): e355-6. doi:10.1043/1543-2165(2003)127e355:PQCAIM2.0.CO;2. PMID 12873205.
  4. URL: http://www.medpath.info/MainContent/Skeletal/Bone_07.html. Accessed on: 18 September 2012.
  5. Kokavec, M.; Gajdoš, M.; Džupa, V. (2011). "[Osteochondroma of the iliac crest: case report].". Acta Chir Orthop Traumatol Cech 78 (6): 583-5. PMID 22217414.
  6. 6.0 6.1 URL: http://path.upmc.edu/cases/case341/dx.html. Accessed on: 19 September 2012.