Flashcards in Bones & Joints Deck (253)
May be asymptomatic.
May cause symptoms if involving sinuses or orbits.
Osteoma: Radiography (3).
Circumscribed; no destructive features.
Involves surface or medulla of bone.
No malignant transformation.
Dense lamellar bone.
Osteoid osteoma: Age group.
Second and third decades.
Osteoid osteoma: Sites (3).
Small bones of hands and feet.
Osteoid osteoma: Presentations (2).
Classic: Pain that is worse at night and relieved by aspirin.
Tumor in hand or foot: Clinically mimics osteomyelitis or arthritis.
Osteoid osteoma: Radiography (2).
Cortical radiolucent nidus, usually less than 1 cm in diameter, surrounded by sclerosis.
Plain radiographs miss about 25% of tumors.
Osteoid osteoma: Histology of nidus (3).
Interlacing trabeculae that are
- Variably mineralized.
- Rimmed by osteoblasts.
- Surrounded by fibrovascular stroma that contains multinucleate giant cells.
Osteoid osteoma: Histology of periphery.
Fibrovascular tissue surrounded by compact lamellar bone.
Osteoid osteoma: What should not be seen within the tumor (3).
Cartilage, unless there had been a fracture.
Osteoid osteoma: Preoperative aids to recognition.
Identification of the nidus may be facilitated by
- Tetracycline: Nidus becomes fluorescence in UV light.
Osteoid osteoma: Mutation.
Partial deletion of 22q in some cases.
Osteoid osteoma: Immunohistochemistry.
Some cases express c-fos and c-jun.
Osteoid osteoma vs. stress fracture.
- Dense, mature bone is in the center.
- Woven bone is in the periphery.
Osteoid osteoma: Why painful (3)?
Unmyelinated axons in the nidus.
Production of prostaglandin E2.
Production of prostacyclin.
Osteoblastoma: Age group.
Occurs mainly in the second and third decades.
Vertebral column and sacrum.
Mandible and other bones of the skull.
A. Location in bone.
A. In the medulla.
B. Not as painful as osteoid osteoma.
Osteoblastoma: Radiography (2).
Expansile radiolucent zone (nidus) with a sclerotic rim.
Nidus is more than 1.5 cm in diameter.
Osteoblastoma: Variations on radiography (3).
Formation of new bone around tumor.
Cortical destruction that mimics osteosarcoma.
Secondary aneurysmal cyst.
Osteoblastoma: Gross pathology (3).
Similar to that of osteoid osteoma, but osteoblastoma is larger.
- Cortical thinning.
- Hemorrhagic (secondary aneurysmal) cyst.
Osteoblastoma: Histology (4).
Irregular osteoid with rimmed by bland osteoblasts.
Osteoid merges into that of normal bone.
Osteoblasts can be mitotically active.
Fibrous stroma containing multinucleate osteoclast-like giant cells.
Osteoblastoma: Variations on histology (2).
Variable mineralization of osteoid.
Large blood lakes (secondary aneurysmal bone cysts).
A. Much cytoplasm, large nuclei, large nucleoli.
B. If they constitute more than 75% of the tumor, then it should be called aggressive osteoblastoma, which is more likely to recur.
A. Pseudo-malignant osteoblastoma.
B. Contains bizarre multinucleate giant cells without mitotic activity.
Osteoblastoma vs. osteoblastic osteosarcoma
- Sarcomatoid stroma.
- Osteoblasts form sheets or aggregates rather than a rim.
Conventional intramedullary osteosarcoma: Sites (3).
- Distal femur.
- Proximal tibia.
- Proximal humerus.
Conventional intramedullary osteosarcoma: Sites in Paget's disease (3).
Bones of the skull.