Bone Formation and Bone Tumors Flashcards Preview

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Flashcards in Bone Formation and Bone Tumors Deck (23):
1

osteoblasts derive from

mesenchymal cells

2

osteoclasts are most like

macrophages--> can form multinucleated cells

3

stimulated by PTH

osteoclasts

4

cartilage replaced by what bone intitially in endochondral ossification

woven bone--> later replaced by lamellar bone, which is stronger

5

what two types of bone are made by membranous ossification

bones of calvarium and facila bones--> woven bone made directly w/o cartilage; also later replaced to lamellar bone

6

defect in achondroplasia

FGFR3--> contsitutively active which inhibits chondrocyte proliferation = short limbs due to early epiphyseal plate closure

7

pattern of inheritance in achondroplasia

autosomal dominant--> homozygotes for the gene are not viable!

8

what can increase risk of achondroplasia

advanced paternal age--> 85% are sporadic mutations

9

MCC benign bone tumor

osteochondroma

10

age range of osteochondroma and characteristic finding

males under 25--> exostosis with cartilaginous cap

*is a type of hamartoma (overgrowth of otherwise normal tissue)

11

benign bone tumor affecting older people. characteristic lesion and where

osteoclastoma (giant cell tumor)--> "soap bubble" appearance on x-ray
*usually around the knee

12

MC bone primary tumor in children

osteosarcoma

13

characteristic age, sex, and 2 lesion seen in osteosarcoma. where?

males under 20; Codman's triangle or sunburst pattern on x-ray, commonly in metaphysis of dital femur or proximal tibia (knee)

*presents as painful knee; ass. w/ hx of radiation, familial RB. hx of bone infarct

14

bone tumor affects boys under 15

Ewing's sarcoma

15

translocation of Ewings

t(11,22)

16

Ewing's commonly appears in what region of what 4 bones

diaphysis of:
1. long bones
2. pelvis
3. scapula
4. ribs

17

characteristic x-ray lesion for Ewings

"onion-skin" lesion

*anaplastic small blue cell malignant tumor; highly aggrssive with early mets, but responsive to chemo

18

malignant bone tumor affecting oldr men

chondrosarcoma

*occurs in diapysis of pelvis, spine, scapula, humerus, tibia or femur

19

5 most likely primary CA to met to bone

1. Prostate
2. Renal cell carcinoma
3. Testes/thyroid
4. Lung
5. Breast

*note the urinary system involvement

20

met producing lytic lesions in bone

lung

21

met producing blastic lesion in bone

prostate

22

PTH at intermittent levels does what

anabolic effect on bone by stimulating osteoclasts and osteoblasts

23

PTH at chronic high levels (hyperparathyroidism)

catabolic effects--> osteitis fibrosa cystica (aka von Recklinghausen disease of bone); is due to excess stimulation of osteoclasts

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