Bones & Joints Flashcards Preview

Anatomic pathology > Bones & Joints > Flashcards

Flashcards in Bones & Joints Deck (253)
Loading flashcards...
1

Osteoma: Presentation.

May be asymptomatic.

May cause symptoms if involving sinuses or orbits.

2

Osteoma: Radiography (3).

Radiodense.

Circumscribed; no destructive features.

Involves surface or medulla of bone.

3

Osteoma: Behavior.

Rarely recurs.

No malignant transformation.

4

Osteoma: Histology.

Dense lamellar bone.

5

Osteoid osteoma: Age group.

Second and third decades.

6

Osteoid osteoma: Sites (3).

Proximal femur.

Vertebrae.

Small bones of hands and feet.

7

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.

8

Osteoid osteoma: Radiography (2).

Cortical radiolucent nidus, usually less than 1 cm in diameter, surrounded by sclerosis.

Plain radiographs miss about 25% of tumors.

9

Osteoid osteoma: Histology of nidus (3).

Interlacing trabeculae that are

- Variably mineralized.
- Rimmed by osteoblasts.
- Surrounded by fibrovascular stroma that contains multinucleate giant cells.

10

Osteoid osteoma: Histology of periphery.

Fibrovascular tissue surrounded by compact lamellar bone.

11

Osteoid osteoma: What should not be seen within the tumor (3).

Cartilage, unless there had been a fracture.

Marrow elements.

Fat.

12

Osteoid osteoma: Preoperative aids to recognition.

Identification of the nidus may be facilitated by

- Tetracycline: Nidus becomes fluorescence in UV light.
- Tc-99m.

13

Osteoid osteoma: Mutation.

Partial deletion of 22q in some cases.

14

Osteoid osteoma: Immunohistochemistry.

Some cases express c-fos and c-jun.

15

Osteoid osteoma vs. stress fracture.

Stress fracture:

- Dense, mature bone is in the center.
- Woven bone is in the periphery.

16

Osteoid osteoma: Why painful (3)?

Unmyelinated axons in the nidus.

Production of prostaglandin E2.

Production of prostacyclin.

17

Osteoblastoma: Age group.

Occurs mainly in the second and third decades.

18

Osteoblastoma: Sites

Vertebral column and sacrum.

Mandible and other bones of the skull.

Extremities.

19

Osteoblastoma:

A. Location in bone.
B. Presentation.

A. In the medulla.

B. Not as painful as osteoid osteoma.

20

Osteoblastoma: Radiography (2).

Expansile radiolucent zone (nidus) with a sclerotic rim.

Nidus is more than 1.5 cm in diameter.

21

Osteoblastoma: Variations on radiography (3).

Formation of new bone around tumor.

Cortical destruction that mimics osteosarcoma.

Secondary aneurysmal cyst.

22

Osteoblastoma: Gross pathology (3).

Similar to that of osteoid osteoma, but osteoblastoma is larger.

Variations:
- Cortical thinning.
- Hemorrhagic (secondary aneurysmal) cyst.

23

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.

24

Osteoblastoma: Variations on histology (2).

Variable mineralization of osteoid.

Large blood lakes (secondary aneurysmal bone cysts).

25

Epithelioid osteoblasts:

A. Cytology.
B. Significance.

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.

26

Bizarre osteoblastoma:

A. Synonym.
B. Histology.

A. Pseudo-malignant osteoblastoma.

B. Contains bizarre multinucleate giant cells without mitotic activity.

27

Osteoblastoma vs. osteoblastic osteosarcoma

Osteoblastic osteosarcoma:

- Sarcomatoid stroma.
- Osteoblasts form sheets or aggregates rather than a rim.

28

Conventional intramedullary osteosarcoma: Sites (3).

Metaphyseal:

- Distal femur.
- Proximal tibia.
- Proximal humerus.

29

Conventional intramedullary osteosarcoma: Sites in Paget's disease (3).

Bones of the skull.

Ribs.

Vertebrae.

30

Conventional intramedullary osteosarcoma: Age groups.

Mainly the second decade.

Some cases occur after 50 years of age.