Bone Tumors Flashcards
osteo vs ewings
osteo metaphyseal, sunburst
- most common distal femur, prox tibia, prox hum
ewings diaphyseal, onion skinning
- most common 50% axial, 40% extremity (lower>pelvic>upper)
Osteo predisposing
RB1
LFS
Rothmund-Thompson syndrome (RECQL4)
Bloom
Werner’s
ionizing radiation
metabolic bone disease (Paget, fibrous dysplasia)
Benign lytic bone lesion DDx
fibrous dysplasia
non-ossifying fibroma
aneurysmal bone cyst
simple bone cyst
LCH
osteoblastoma
Osteosarcoma common genetic alterations
genomic instability (chromothripsis)
TP53 (>90%)
RB1 inactivation (70%)
LOH13q (60%)
PI3K/mTOR (15%)
CDK4 amplification (10%)
ATRX, DLG2 mutations
Ewing staging
CT/MRI primary site
CT chest
b/l BMA/B
PET (bone scan)
biopsy
Osteosarcoma histology subtypes
Osteoblastic (80%)
Chondroblastic (10%): cartilaginous matrix
Fibroblastic (10%)
telangiectatic: pure lytic
Small cell
Pariosteal
Parosteal
Osteosarcoma tx schema
neoadj chemo
resection
adj chemo
+- metastatectomy
MAP: MTX, doxo, cisplat
Osteosarcoma ix
XR
CT/MRI primary site
CT chest
PET/bone scan
biopsy (surgical or core, by resection surgeon)
Osteosarcoma tumor necrosis cutoff
good 90+%
poor <90%
osteosarcoma vs Ewing mets
osteo: lung (up to 90%), skip lesions, bone
Ewing: lung > bone > BM
- 10-30% upfront
Osteosarcoma px
non-metastatic extremity
- poor responder 40%
- good responder 80%
- allcomers 60%
Metastatic
- lung only 30-50%
- widely <5-10%
osteosarcoma px factors
worse:
- <5yo
- M
- pelvic, axial
- mets
- larger size
- poor responder
Ewing Sarcoma presentation
pain
soft tissue mass - uncommon in osteo
20% B symptoms - uncommon in osteo
Ewing px factors
good:
- no mets
- younger
- <8cm
- extrem
- F>M
Ewing sarcoma genetics
t(11;22) EWSR1-FLI1 (90%)
t(21;22) ESR1-FUS
