A 17-year-old boy with osteosarcoma of the distal femur is being assessed for limb salvage surgery. According to the Enneking surgical staging system, a Stage IIB lesion is defined as:
- A High-grade tumour extending beyond the cortical bone into surrounding soft tissues (extracompartmental) ✓
- B High-grade tumour confined within the cortical bone (intracompartmental)
- C Low-grade tumour with regional lymph node metastasis
- D High-grade tumour with distant metastasis regardless of local extent
Correct answer: A. High-grade tumour extending beyond the cortical bone into surrounding soft tissues (extracompartmental)
Explanation
The Enneking system stages bone sarcomas based on grade (I = low, II = high), local extent (A = intracompartmental, B = extracompartmental), and metastasis (Stage III = any grade with metastasis). Stage IIB is a high-grade tumour that has breached the cortex/compartmental barrier into surrounding tissues, which worsens the prognosis and affects surgical planning by requiring wider margins. Stage III involves metastatic disease.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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