Presentation
Swelling and pain at multiple levels around knee joint
Patient Data
There are multiple bony outgrowths arising from distal femur and proximal tibia and fibula. They project away from the knee joint and have a "coat hook" configuration. The cortex of these bony excrescences is continuous with the parent bone. There is a sessile type bony excrescence at the proximal fibular head. These bony excrescences are compatible with osteochondromas.
Multiple osteochondromas in a patient are consistent with multiple hereditary exostoses.
Case Discussion
Osteochondromas are the benign bone outgrowths which can be single or multiple. They can transform to malignant lesions. There is more malignant potential when they are multiple as compared to a single lesion. These lesions are typically found around the joints and grow away from the joint with the cortex of lesion in the continuity with the parent bone. They can be of sessile or peduncular variety. The signs for the malignant transformation include pain and increase in size. CT and MRI are helpful to evaluate these lesions when there is a concern of malignancy.