Osteochondroma

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

Exostosis^[2] redirects here.

General

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:

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:

www:

↑ ^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.
↑ ^2.0 ^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.
↑ ^3.0 ^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.
↑ URL: http://www.medpath.info/MainContent/Skeletal/Bone_07.html. Accessed on: 18 September 2012.
↑ 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.
↑ ^6.0 ^6.1 URL: http://path.upmc.edu/cases/case341/dx.html. Accessed on: 19 September 2012.