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Multiple Osteochondromatosis N060

Last amended 
13 April 2021
Current RMA Instruments
Reasonable Hypothesis SOP
43 of 2015
Balance of Probabilities SOP
44 of 2015
Changes from previous Instruments

SOP Bulletin 111

ICD Coding
  • ICD-9-CM Codes: 756.4
  • ICD-10-AM Codes: Q78.6
Brief description

This is a genetic disorder of the bone manifesting in multiple benign cartilage topped bone tumours arising from the growth plates.

Confirming the diagnosis

This diagnosis is based on clinical findings and imaging of the bone with MRI [magnetic resonance imaging], CT [computerised axial tomogram], or plain x-rays.  Histology may be obtained.

The relevant medical specialist is an orthopaedic surgeon.

Additional diagnoses covered by SOP
  • Nil
Conditions excluded from SOP#
  • Dysplasia epiphysealis hemimelica
  • Enchondromatosis
  • Metachondromatosis
  • Ollier disease
  • Single osteochondroma
  • Synovial osteochondromatosis

All non-SOP

Clinical onset

The genetic abnormality is present from birth.  The osteochondromas develop before adulthood (before bone growth ceases).  They are mostly asymptomatic but may cause pain, disfigurement or compression of adjacent structures. They are most frequently located in the long bones and particularly around the knee. 

Clinical worsening

The only SOP factor is for inability to obtain appropriate clinical management. 

Lesions cease to grow when the bone growth-plates close in early adulthood.  Mangement involves observation and surgical excision for troublesome lesions.  Malignant transformation to chondrosarcoma occurs rarely.  This would be onset of a new condition rather than worsening of osteochondromatosis.