MSK neoplasms Flashcards
MC 1˚ osseous malignancies
MM/plasmacytoma (27%), OS (20%), CS (20%)
how much trabecular bone is destroyed before you can see it?
70%
what demonstrates permeative & moth eaten app?
myelin, lymphoma, ewings, OM, hyperPTH
4 main subtypes OS to know
1) conventional intramedullary (85%, higher grade than surface types)
2) parosteal (4%)
3) periosteal (1%)
4) telangiectatic (rare)
Difference btw trabecular vs cortical bone loss
Trabecular more rapidly but noticed later bc cortical bones more smooth & orgz
conventional intramedullary-1˚ vs 2˚, where, bf’s, classic met
- 1˚ 10-20 yr old
- femur (40%), prox tibia (15%)
- skip lesions, lung (occult PTX)
class OS PW
xray –> bone scan + Chest CT –> MRI (entire bone for skip lesions, bx planning) –> bx –> neoadjuvant chemo –> restage, re biopsy –> surgery –> adjuvant chemo –> f/u (2 yrs)
- re-biopsy: predicts outcome (90% tumor death = good)
- 2 yr f/u: 80% relapse –> lung. 20%–> bone
Parosteal OS
low grade, bulky/big
- pst distal femur (mimic cortical dermoid tug lesion early on )
- meatphyseal 90%
- string sign-radiolucent line sep bulky tumor from cortex.
sunburst pattern
aggressive periosteal run looks like sunburst
“reverse zoning phenomenon”
denser mature matrix in center, less peripherally (opposite of myositis ossificans)
BWs aggressive periosteal reactions
- Sunburst
- Reverse zoning phenomenon
- Lamellated
- Codman triangle
“lamellated”/onion skin rxn
multi layers of parallel peritoneum
Codman triangle
edge of raised periosteum ossifies creating appearance of triangle
parosteal vs periosteal osteosarcomas- who, where, marrow ext, grade/outcome
- Parosteal: early adult/middle age, metaphyseal, pst distal femur, marrow ext 50%, low grade, extends OUTWARD
- Periosteal: 15-25 yo, diaphysial, medial distal femur, no marrow extension, intermediate grade (worse outcome)
Telangiectatic OS-classic app
- 15% narrow zone
- Rgx: cystic
- MR: F/F levels, T1+ (methemoglobin)
Order of OS grade/outcome
Parosteal Periosteal Telangectatic Classic 2˚
Ewing’s
- 2nd MC 1˚bone malignancy in peds. ~15 yo. Rare in AA
- metadiaphysis –> diaph –> metaph
- permeative, moth eaten. +lamellated, ST 80% (Ca-)
- met –> bone (spine) (MC), lung
MC sarcoma to met to bone
Ewings
chondrosarcoma-what, RFs, where, met, matrix
- low grade tumor in older adults (40-70), M > F
- RFs: Paget’s, anything cartilaginous (OC, Maffucci), etc)
- proximal tubular bones (more abundant cartilage) & limb girdles (triradiate cartilage in pelvis)
- central (intramedullary) or peripheral (at end of osteochondroma)
- met –> lung
- “changing matrix”-vs enchondroma
chordoma
- adults 30-60 yr old
- sacrum (slightly older), clivus (slightly younger), VB (C2)
- midline, T2+++
MC 1˚ malignancy of spine
chordoma
MC 1˚ malignancy of sacrum
chordoma
where in spine does chordoma occ
VB C2
Enchondroma vs low grade chondrosarcoma-what favors chondrosarcoma?: pain, cortex, size, matrix
- Pain
- Cortical destruction (scalloping >2/3),
- > 5cm
- changing matrix