Enneking surgical staging system

Dr Yuranga Weerakkody and Dr Henry Knipe et al.

The Enneking surgical staging system (also known as the MSTS system) is based on tumor grade, local spread and metastatic disease of malignant musculoskeletal tumors.

It does not classify skull tumors or marrow-originating tumors (e.g. lymphoma, plasmacytoma / multiple myeloma, Ewing sarcoma) 1. It is widely accepted and used by orthopaediac surgeons given its compartment-based classification. 


  • stage Ia
    • low-grade (G1)
    • intracompartmental (T1)
    • no metastases (M0)
  • stage Ib
    • low-grade (G1)
    • extracompartmental (T2)
    • no metastases (M0)
  • stage IIa
    • high-grade (G2)
    • intracompartmental (T1)
    • no metastases (M0)
  • stage IIb
    • high-grade (G2)
    • extracompartmental (T2)
    • no metastases (M0)
  • ​stage III
    • low or high-grade (G1 or G2)
    • intra- or extra-compartmental (T1 or T2)
    • distant metastases (M1)

Low-grade corresponds to Broder grade 1 or 2 (<25% chance metastases) and high-grade corresponds to Broder grade 3 or 4 1

Bone tumours

The differential diagnosis for bone tumors is dependent on the age of the patient, with a very different set of differentials for the pediatric patient.

Article information

rID: 40747
Section: Staging
Tag: cases
Synonyms or Alternate Spellings:
  • Surgical staging system (MSTS system)
  • MSTS system

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