The neoplasms in this category all form osseous matrix and are divided into benign and malignant tumors. Although bone islands and osteomas are not classified by the World Health Organization (WHO) as true tumors, they are included here under benign osteogenic tumors for simplicity and due to their common occurrence. Bone islands and osteomas appear as dense lesions within and on the surface of bone, respectively, and the major concern is distinguishing them from sclerotic metastases. Osteoid osteomas and osteoblastomas are bone-forming tumors with a central highly vascular nidus and are often surrounded by dense reactive sclerosis. They are nearly identical histologically, and the distinction is made based on imaging. Osteoid osteomas have a nidus smaller than 2 cm and are more common in the appendicular skeleton. Osteoblastomas have a nidus greater than 2 cm, and have a more varied appearance, ranging from a dense lesion with a poorly visualized nidus to an expansile lytic lesion. Osteoblastomas also have a more varied clinical presentation than osteoid osteomas and may not respond to aspirin.
KeywordsAspirin Sarcoma Myeloma Osteosarcoma Osteomyelitis
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