Joint Program in Nuclear Medicine
Osteosarcoma
Jan Stauss
S. Ted Treves, MD
July 31, 2002
Presentation
An eleven year old boy presents with knee pain four weeks after knee injury during a
basketball game. His physical examination is unremarkable.
Imaging Findings
Planar whole body imaging was performed and demonstrates heterogeneous areas of high and
low uptake in the left distal femoral metadiaphysis (show by arrow). Additional views of
the right arm, skull, and the left arm did not reveal any other focal uptake abnormality.
After surgery a follow-up bone scan demonstrates an osteoarticular allograft as
photopenic area in the region of the left distal femur
(show by arrow). The focus of
increased uptake in the left distal humerus is attributable to the injection of tracer
at this site.
Diagnosis
Osteosarcoma of the left distal femur
Discussion
Osteosarcoma is the most common primary malignancy of bone and occurs predominantly in
teenagers and young adults. The incidence is 400 cases per year in the US and males are
slightly more often affected. Half of the lesions are located in the distal femur or
proximal tibia. The proximal humerus, proximal femur and pelvis are the next most common
sites (1). Patients may present with pain and swelling, but usually do not have systemic
symptoms and feel well. On physical examination the mass typically is slightly tender,
firm, and fixed to the bone. On laboratory studies alkaline phosphatase and lactate
dehydrogenase can be elevated. Usually osteosarcoma is discovered on plain radiographs
revealing bony destruction, elevation of the periosteum that may appear as the
characteristic Codman triangle and in some cases a contiguous soft tissue mass. A CT of
the primary lesion to delineate the location and a high resolution CT scan of the chest
to rule out pulmonary metastases should be obtained. Skeletal scintigraphy, which
typically shows a defined region of increased tracer uptake, is useful to determine the
extent of the lesion, to evaluate for metastases to the bone, and for early detection of
local recurrence(2). The importance of follow-up bone scans is underscored by a study
performed at the Children's Hospital Boston, in which only two of fifty-six patients
with osteosarcoma had metastatic disease at presentation, but 57% developed osseous or
pulmonary metastases during the follow-up period (3). Treatment typically consists of
adjuvant and neoadjuvant chemotherapy with surgical resection of the lesion. In some
cases amputation of the limb cannot be avoided.
References
1. Springfield DS: Bone and soft tissue tumors. In: Morrissy RT, Weinstein SL: Lovell
and Winter's Pediatric Orthopaedics, fourth edition. Philadelphia, Lippincott, 1996, pp
423-468.
2. 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.
3. Goldstein H, McNeil BJ, Zufall E, Jaffe N, Treves ST: Changing indications for bone
scintigraphy in patients with osteosarcoma. Radiology 135: 177-180, 1980.
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