Osteoclastoma: Rare Bone Tumour Seen on a Bone Scan
Osteoclastoma is an aggressive rare bone tumour. It is shown to be malignant in 5-10%, where it can spread to other bone or lungs. The main imaging used to detect and assess osteoclastoma is plain x-ray. It can be seen on all imaging modalities and is seen in bone scans as diffuse uptake throughout the tumour.
This patient was a 49 year old male who had presented to emergency with left knee pain and a cracking sensation whilst kneeling. Both plain x-ray and CT showed a large hypodense lesion in the distal left femur and a bone scan was arranged to exclude any other bony lesions. The bone scan showed significantly increased uptake in the left medial condyle, with no other bony lesions seen. SPECT imaging confirmed a central photopenic area and that the lesion involves the articular surface of the femur.
Treament involved surgery to remove the lesion from the femur and replace it with bone cement. Pathology of the removed lesion confirmed the diagnosis of osteoclastoma. Further surgery three months later has replaced the bone cement, with surgery of joint replacement planned for the future. Eighteen months post initial surgery there has been no recurrence of the tumour.
The bone scan was able show the tumour was metabolically active, show no other bony lesions and show the articular surface of the joint was involved. These all helped to confirm that surgery was required to remove the lesion.