Non-ossifying fibroma of the proximal tibia mimicking chronic osteomyelitis in a child.

A boy in his early teens presented with gradually progressive pain and swelling over the anterior aspect of the left upper leg. The insidious onset and firm swelling suggested an infective aetiology, and a provisional diagnosis of chronic osteomyelitis was made. Radiographs demonstrated a well-demarcated lytic lesion in the metaphyseal region of the proximal tibia, further strengthening the clinical suspicion of infection. However, curettage of the lesion and subsequent histopathological analysis revealed a benign fibro-osseous lesion consistent with non-ossifying fibroma (NOF). The patient underwent surgical debridement followed by analgesics, antibiotics, calcium supplementation and guided physiotherapy. He recovered uneventfully, mobilising with support at discharge. This case highlights the diagnostic challenge posed by NOF when it clinically and radiographically mimics chronic osteomyelitis, underscoring the importance of a multidisciplinary approach incorporating radiology, pathology and orthopaedic input in establishing the correct diagnosis and management strategy.