Synonyms

• MHE
• exostoses

Category

Bone

Behaviour

Benign

Gender

Male

Tissue of Origin

Cartilage

Epidemiology

• Most common Bone tumour overall
• Peak incidence childhood to early adulthood
• Solitary or multiple (hereditary multiple exostoses)
• EXT gene mutations in HME

Clinical Features

• Bony protuberance
• Usually asymptomatic
• Pain if compressing adjacent structures
• Limb length discrepancy in HME

Location

• Femur (most common)
• Tibia
• Humerus
• Pelvis
• Other long Bones

Imaging

• Plain radiograph: bony exostosis with Cartilage cap
• MRI: assess Cartilage cap thickness and underlying lesion
• Ultrasound: measure Cartilage cap

Pathology

• Cartilage-capped bony exostosis
• Hyaline Cartilage cap with endochondral ossification beLow

Genetics

EXT1/2 mutations in hereditary form

Treatment

• Observation for asymptomatic lesions
• Surgical excision if symptomatic or cartilage cap >2 cm

Prognosis

Benign: Malignant transformation rate <1% for solitary, 1-5% for HME

Key Points

• Most common bone tumour
• HME carries malignancy risk
• Monitor cartilage cap size on imaging

Workup - Blood Tests

No blood tests required

Workup - Local Imaging

• Plain radiograph
• MRI: assess Cartilage cap and monitor for malignancy

Workup - Biopsy

Not required unless malignancy concern

Workup - Staging

No staging required

Workup - Other

• Genetic counselling for HME
• Surveillance imaging for multiple lesions/HME

Follow-up Summary

• Observation asymptomatic lesions
• Resection for symtomaitc lesions. Post-operative follow-up at 6 weeks followed by supported discharge
• Annual surveillance for MHE patints