A 15-year-old male presents with night pain relieved by aspirin. Plain X-ray shows a small <2 cm lucent nidus surrounded by dense reactive cortical sclerosis in the proximal femur. What is the most likely diagnosis and definitive treatment?
- A Osteoid osteoma — CT-guided radiofrequency ablation ✓
- B Eosinophilic granuloma — radiation therapy
- C Brodie's abscess — antibiotics and surgical drainage
- D Osteoblastoma — surgical curettage
Explanation
Osteoid osteoma is a benign bone-forming tumour characteristically presenting in young males with nocturnal pain dramatically relieved by NSAIDs/aspirin (due to prostaglandin E2 production within the nidus). The classic radiological finding is a small (<2 cm) lucent nidus (with or without central calcification) surrounded by dense disproportionate reactive cortical sclerosis. CT is the gold standard for nidus identification. Definitive treatment is CT-guided radiofrequency ablation (RFA) which has replaced surgical excision. Osteoblastoma is >2 cm, more expansile, lacks the sclerotic response, and requires surgical excision.
Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.
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Written and medically reviewed by the StethoPrep medical team.