Contribution of Bone Radionuclide Imaging in the Etiological Diagnosis of a Knee Tumor: A Case Report

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Introduction: Primary malignant bone tumors are rare (1% of all neoplasia) and often of late discovery. We observed a case discovered on technetiated diphosphonate (^99mTcMDP) bone scan after 5 months of radiological diagnostic errancy.

Methods/Observation: This was a 20-year-old man who had presented for 5 months with a painful swelling of the right knee. An X-ray of the knee performed 3 days after the onset of the symptomatology was unremarkable. An ultrasound and a CT scan performed 2 months later revealed a lesion of the right femur, suggesting chronic osteoarthritis. In view of the increasing volume of the swelling, despite a well-conducted anti-infectious treatment, a bone scan was performed after IV injection of 640 MBq of ^99mTc-MDP.

Results: The scan revealed a hyper-fixation zone in the right femorotibial bone, raising the suspicion of a primary tumor lesion of the probable chondrosarcoma type. The biopsy performed evoked a round cell bone tumor in favor of either a plasmacytoma or a lymphoma. The patient was referred to oncology for management.

Conclusion: This clinical case highlighted the interest of early scintigraphy in rapidly evolving bone pathologies.

Publication History

Article published online:
25 May 2023