Incidence
- About 1% of benign bone tumours
- Male : Female 2:1
- Peak age 10 – 20 years (rare over 30 years)
- 50% happen in the lower limbs
- Epiphysial
Clinically
- Present with ache of increasing severity
- Usually affects
- Distal femur
- Proximal tibia
- Proximal humerus
- Tri-radiate cartilage
- May affect calcaneus (Codman’s tumor)
- Physical exam may reveal
- Local tenderness
- Painful ROM
- Limping
- Less than 5% metastasise to lung
X-Rays
- Well defined area of rarefaction centered in the epiphysis
- Commonly epiphyseal, but may expand into metaphysis
- Negligible sclerotic reaction in surrounding bone
- 50% show central calcification
- 50% show linear periosteal reaction
- Bone scan shows increased uptake at margins
Pathology
- Possible association with Chromosome 5 and 8 abnormality
- Cell origin :
- ? enchondral plate
- ? reticulohistiocytes
- 20% have associated ABC changes
- Usually active benign lesion (Stage 2)
- Histology shows pinkish grey tissue :
- <3 cm
- Lobulated
- May be haemorrhagic (secondary ABC)
- Calcified matrix may take the characteristic "chicken wire" look
- Richly cellular, including :
- Multinucleate giant cells (not to be confused with GCT)
- Polyclonal or round chondroblasts
Treatment
- Marginal excision plus bone graft, if not involving the joint
- Use cryotherapy, if extends to intra-capsular space to avoid excision of joint
- Rarely takes aggressive form
Prognosis
- 90% cure rate
- Rare chance of malignant transformation, if any
References
- Lonner J.H, Steiner G.C and Kenan S : Cartilage-forming Tumors. In Spivak JM, Di Cesare PE, Feldman DS : Orthopedics; A Study Guide; 1999
- Frassica F.J, Frassica D.A and McCarthy E.F : Orthopedic Pathology. In Mark D. Miller : Review of Orthopedics; 2008
