Tumor and Tumorlike Lesion of Bone Osteoma Osteoma

Tumor and Tumor-like Lesion of Bone

Osteoma • Osteoma is a benign mass protruding from osseous tissue

Osteoma • Most common tumor of the paranasal sinuses, most frequently seen in the frontal sinus and ethmoids • Two varieties are described: the dense 'ivory' type and 'cancellous' osteoma

（a) (b) Osteoma Lateral radiograph of the skull (a) and axial CT scan (b) demonstrate an ossific nodule (arrow) arising from the outer table of the calvarium

Giant cell tumor • Giant cell tumor is a locally aggressive neoplasm • The sites affected most frequently are the long tubular bones

Giant cell tumor • Clinical manifestation • Earliest manifestations include pain, local swelling, limitation of motion and pathologic fractures

Imaging feature • On radiographs, the long and short tubular bones reveal eccentric osteolytic lesions • With MR imaging, intraosseous fluid levels may be seen

Giant cell tumor a, b. AP (a) and lateral (b) radiographs of the knee demonstrate an eccentric osteolytic lesion in the proximal tibia. The lesion has a nonsclerotic border and abuts the articular surface of the tibia.

c. Sagittal T 1 -weighted MR image of the knee demonstrates the low signal intensity mass in the proximal tibia. d. Fat-suppressed T 1 -weighted MR image after gadolinium adminstration demonstrates enhancement of the mass in the proximal tibia.

Giant cell tumor osteolytic lesion in the distal radius soap bubble expandability Soft tissue swelling

Bone cyst • Bone cyst is a usually cavitary lesion of bone. • Bone cysts may occur after trauma and in osteoarthritis

• These cysts occur most frequently in long tubular bones, especially the metaphysis, and in the bony pelvis

Imaging feature • Radiographically, these lesions appear radiolucent and are located centrally, with cortical thinning and mild expansion of the bone • CT scanning and MR imaging with contrast enhancement reveal presence of fluid within the lesion

• Complications of simple bone cysts include complete and incomplete fractures, and (rarely) malignant transformation

Bone cyst Simple bone cyst. AP radiograph of the shoulder demonstrates a pathologic fracture through the simple bone cyst in the humeral metaphysis. Note the "fallen fragment" within the bone cyst.

Osteosarcoma • Osteosarcoma is a malignant neoplasm of bone composed of proliferating tumor cells that in most instances produce osteoid or immature bone

Clinical feature • 75% of cases occurring between the ages of 10 and 25 years • 86% occur in the long bones with the distal femoral metaphyseal region • The next commonest sites are the upper tibia and humerus

Clinical feature • The commonest presentation is pain in the affected area or, occasionally, a pathological fracture • This tumor metastasises early, particularly to the lungs and other bones

Imaging feature • On the radiograph, the tumor may be purely lytic or sclerotic , or a mixture of the two

Imaging feature • Pure lytic lesions vary from areas of • diminished bone density to completely lytic areas with very little reaction from the bone They may have a very thin periosteal reaction overlying the lesion with very little evidence of new bone formation

Imaging feature • The sclerotic osteogenic sarcomas may produce a region of dense sclerosis with loss of the inner cortical margins • The periosteal reaction may be laminated or spiculated with so-called 'sunburst' appearance

Imaging feature • More often the tumors are both lytic and sclerotic with destruction of the bone and cortex, and extension into the soft tissues • There may be a variable amount of calcification in the soft tissues • a prominent periosteal reaction with a Codman's triangle

• MRI: • The lytic areas of the tumor show a low signal on T 1 and high signal on T 2 • The extension in the medullary cavity is very accurately determined by MRI, as is the soft tissue extent

Osteosarcoma AP (a) and lateral (b) radiographs of the femur demonstrate a large soft tissue mass with an aggressive periosteal reaction creating the sunburst appearance. Patchy osteosclerosis and osteolysis in the distal femur

Osteogenic sarcoma Osteolytic sarcoma of the fibular head. There is a small amount of calcification within the tumor.

Osteogenic sarcoma Osteoblastic sarcoma in the upper metaphyseal region of the tibia. There is sclerosis, breach of the cortex and sclerotic extension of the tumor into the tissues. The cortical margin is lost

Osteogenic sarcoma Radiograph of a distal femoral osteogenic sarcoma. On the radiograph there is a mixed sclerotic and lytic lesion with a layered periosteal reaction anteriorly and showing calcification.

Osteogenic sarcoma The large soft tissue component is well seen on the MR. There is high signal within the lesion and in the medullary cavity