Joint Program in Nuclear Medicine

Osteoid Osteoma

Jan Stauss
S. Ted Treves, MD

July 31, 2002

Presentation

A 13-year-old male presents with pain in his left index finger, predominantly present at night and responding to antiinflammatories.

Imaging Findings

A three phase bone scan was performed. Radionuclide angiography (shown by arrow) and tissue-phase imaging (show by arrow) of the hands both demonstrate focally increased tracer uptake at the base of the proximal phalanx of the left index finger. Delayed bone-phase images (marker on the right, shown by arrow) show focally increased uptake in the same location, well appreciated on the additional pinhole view (shown by arrow).

Differential Diagnosis

Diagnosis

Osteoid osteoma of left index finger

Discussion

Osteoid osteoma is a benign lesion that accounts for approximately 10% of benign bone tumors. It occurs predominantly in children and young adults between 10 and 25, affecting males twice as often as females. The clinical presentation typically consists of pain, which is often worst at night, increased skin temperature, sweating, and tenderness in the affected region. Pain is completely relieved by salicylates in many cases.

Predilection sites are proximal femur, and diaphysis of long bones, which account for more than half of all cases, and less often foot and the posterior elements of the spine (1). Osteoid osteomas are usually detected on radiographs, typically showing a radiolucent nidus surrounded by sclerosis in the cortex of the bone. If an osteoid osteoma is suspected and radiographs are negative, skeletal scintigraphy is especially useful with a sensitivity of 100% (2). Radionuclide angiography and tissue-phase imaging often, but not always, show prominent tracer delivery and early localization. On skeletal-phase images a well-localized, focal tracer uptake is typically noted (3). Characteristic is a cloud of diffuse increase of radiotracer around the prominent focus, which is better seen on images obtained with pinhole magnification technique (4). In complicated cases computed tomography might be helpful to visualize the nidus. Scintigraphy also is contributory for treatment of patients with osteoid osteoma by ensuring complete removal of the lesion. This can be achieved either by imaging the specimen that should demonstrate a normal margin of bone around the lesion or intraoperatively with a mobile gamma camera, demonstrating that no residual activity suggestive of osteoid osteoma tissue is left (5).

References

1. Treves ST, Connolly LP, Kirkpatrick JA, Packard AB, Roach P, Jaramillo D: Bone. In: Treves ST (ed): Pediatric nuclear medicine, second edition. New York, Springer-Verlag, 1995, pp 233-301.

2. Lisbona R, Rosenthall L: Role of radionuclide imaging in osteoid osteoma. Am J Roentgenol 132: 77-80, 1979.

3. Connolly LP, Treves ST: Assessing the limping child with skeletal scintigraphy. J Nucl Med 39: 1056-1061, 1998.

4. Roach PJ, Connolly LP, Zurakowski D, Treves ST: Osteoid osteoma: comparative utility of high resolution planar and pinhole magnification scintigraphy. Pediatr Radiol 26: 222-225, 1995.

5. Sty J, Simons G: Intraoperative 99m technetium bone imaging in the treatment of benign osteoblastic tumors. Clin Orthop 165: 223-227, 1982.

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J. Anthony Parker, MD PhD, Tony_Parker@CareGroup.Harvard.edu