Acute osteomyelitis shown as a cold lesion on bone scan

Acute osteomyelitis is usually shown as a localized area of increased activity (hot uptake) in the infectious focus on bone scintigraphy. In our patients, absence of radioactivity (cold lesion) was noted in the distal metaphyseal and diaphyseal regions of his right femur. Initial x-ray was interpreted as normal except for mild soft tissue swelling in the right thigh. The lesion was confirmed as an acute osteomyelitis with subperiosteal abscess on surgery. Staphylococcus aureus was the etiologic organism. We describe a case of acute osteomyelitis in a one-year-old boy shown as a cold lesion on bone scan