OSTEOBLASTOMA Figure 4-38 OSTEOBLASTOMA A: The osteoblastoma is confined by a layer of reactive sub periosteal bone. The tumor is solid and composed of inter connecting trabeculae of woven bone. B: Islands of cellular tumor contain mineralized bone, well-defined by subperiosteal reactive bone. ... More

OSTEOBLASTOMA-LIKE OSTEOSARCOMA Figure 5-34 OSTEOBLASTOMA-LIKE OSTEOSARCOMA Left: Osteoblastoma-like osteosarcoma grows with an infiltrative pattern, encasing preexisting bone. Right: Neoplastic bone is rimmed by plump osteoblasts. The intertrabecular spaces contain loose connective tissue with ... More

OSTEOBLASTOMA Figure 4-45 OSTEOBLASTOMA Ki-67 immunohistochemical stain of conventional osteoblastoma shows that many tumor cells are positive. More

OSTEOBLASTOMA Figure 4-40 OSTEOBLASTOMA A: A sheet-like deposit of woven bone is seen. B: Neoplastic rimming osteoblasts are of medium size with abundant eosinophilic to amphophilic cytoplasm. Many nuclei are polarized away from the bone-forming surface. Scattered osteoclasts are present on the ... More

OSTEOBLASTOMA Figure 4-37 OSTEOBLASTOMA Curetted tumor is composed of fragments of red-tan tissue. More

OSTEOBLASTOMA WITH CARTILAGE Figure 4-42 OSTEOBLASTOMA WITH CARTILAGE Left: Nodule of well-formed hyaline cartilage abuts neoplastic bone. Right: In areas, the cartilage merges with the tumor bone. More

OSTEOBLASTOMA WITH PSEUDOMALIGNANT CHANGE Figure 4-44 OSTEOBLASTOMA WITH PSEUDOMALIGNANT CHANGE Left: Neoplastic osteoblasts have enlarged hyperchromatic nuclei. Right: The nuclear enlargement, hyperchromasia, smudging, and vacuolization in pseudomalignant change is hypothesized to be related to... More

OSTEOBLASTOMA Figure 4-31 OSTEOBLASTOMA Left: Frontal radiograph of the spine showing loss of normal outline of the left T11 pedicle (white arrow), indicative of destruction of the pedicle by tumor. Right: Sagittal fat-suppressed T2-weighted MRI shows an expansile, well-defined mass with fluid-f... More

OSTEOBLASTOMA Figure 4-35 OSTEOBLASTOMA Left: Frontal radiograph shows an intramedullary lytic and sclerotic lesion that extends through the cortex, displaces the periosteum, and has deposited a rim of reactive bone. The margins are difficult to appreciate. Right: Coronal fat suppressed T2-weigh... More

OSTEOBLASTOMA Figure 4-39 OSTEOBLASTOMA A: Needle biopsy specimen shows aggregates of tumor well delineated from subperiosteal reactive bone. B: Haphazardly oriented trabeculae of woven bone are prominently rimmed by plump osteoblasts. The intertrabecular tissue is composed of loose vascular con... More

OSTEOBLASTOMA Figure 4-36 OSTEOBLASTOMA A: Lateral radiograph of the elbow shows a mixed lytic and sclerotic lesion arising from the proximal ulna and extending into the adjacent soft tissues. Associated osteopenia is present. B: Axial T2-weighted MRI shows multiple fluid-fluid levels (ABC-like ... More

OSTEOBLASTOMA Figure 4-34 OSTEOBLASTOMA A: Axial CT image shows a large tumor of the occiput that is delineated peripherally by a thin rim of reactive bone. Most of the tumor is low in attenuation. An area of high attenuation represents neoplastic bone. B: Axial T2-weighted MRI shows that much o... More

OSTEOBLASTOMA Figure 4-32 OSTEOBLASTOMA A: Axial CT image of the cervical spine shows an expansile well-defined mixed sclerotic and lytic tumor of the left pedicle and spinous process. B: Frontal radiograph of the knee shows a mildly expansile, well-defined lytic lesion involving the distal femo... More

OSTEOBLASTOMA Figure 4-33 OSTEOBLASTOMA A: Oblique radiograph of the hip shows a mixed lytic and sclerotic lesion involving the lesser trochanter. The periphery of the tumor is not surrounded by a rim of reactive bone. B: Coronal reformatted CT image shows a heterogeneous ill-defined lesion cent... More