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