The image shows several bony trabeculae with uneven mineralization. The trabeculae are lined by single layer of osteoblasts. Loose fibrovascular stroma fills the intervening space. The bony trabeculae of osteoblastomas are usually thick and well-formed in contrast to thin, lace-like osteoid of osteosarcomas. Secondary aneurysmal bone cyst formation is seen in about 10% of osteoblastomas.