X-rays revealed a non-displaced transverse fracture of the patella as well as a lucent geographic patellar lesion with mineralized margins.
MRI was consistent with an aneurysmal bone cyst occupying approximately 75% of the patella, with associated pathologic fracture.
Histology of the incisional biopsy illustrated multi-nucleated giant cells in the cyst wall and the cystic space, consistent with an aneurysmal bone cyst.
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