Findings

Plain radiographs demonstrated a 1 cm circular subchrondral lucency in the distal aspect of the middle phalanx (arrow) surrounded by a dense rim of sclerosis and mild bony expansion. Minimal periosteal reaction and significant surrounding soft tissue swelling were noted. Chronic osteomyelitis was suspected and the patient was sent for a bone scan. On blood pool images (palmar, volar) at ten minutes and delayed images revealed a focal, well-delineated area of markedly increased activity was observed in the region corresponding to the radiographic abnormality. On delayed bone scintigraphy (palmar, volar, lateral), a focal region of marked increased activity was seen in the same region. An osteoid osteoma was diagnosed at biopsy.

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J. Anthony Parker, MD PhD, jap@nucmed.bih.harvard.edu