Using the Enneking staging system modified for benign bone tumours, a lesion that breaches the cortex and extends into surrounding soft tissue through the periosteal reaction, with a poorly defined margin, is classified as:

• A Stage 1, latent
• B Stage 3, aggressive ✓
• C Stage 2, active
• D Stage IIB, high grade extracompartmental

Explanation

Benign tumours are graded latent (stage 1, stays within bone, heals spontaneously, eg non-ossifying fibroma), active (stage 2, progressive growth limited by cortex and reactive tissue, eg solitary bone cyst) and aggressive (stage 3, penetrates cortex into soft tissue, eg giant cell tumour and aneurysmal bone cyst variants). The Roman numeral stages IIB apply to malignant lesions under the main Enneking system and cannot be applied here.

Reference: Campbell's Operative Orthopaedics, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.