Description of aneurysmal bone cyst
- largely lytic lesion located in metaphysis
- multiple septations within lesion
- narrow zone of transition, well defined border, marked cortical thinning
- lesion confirmed to bone and does not invade into surrounding soft tissue
- no pathological #
Differentials for bone lytic lesions
FOG MACHINES •Fibrous cortical defect / Fibrous dysplasia •Osteosarcoma •Giant cell tumours •Metastases •Aneurysmal bone cyst •Chondromyxoid fibroma OR Chondroblastoma •Hyperparathyroidism (Brown Tumour) •Infection (Osteomyelitis) - ddx for all tumor •Non-ossifying fibroma •Eosinophilic granuloma •Simple bone cyst
Mgx of bone cyst
- simple
- aneurysmal
Simple: watchful waiting (resolve spontaneously), avoid activity which may cause pathological # intralesional steroids aspiration of cyst curettage and fill with bone chips
Aneurysmal:
Curettage and bone grafting
types of bone tumor/lesion by region
- in epiphysis
- in metaphysis
- in diaphysis
- non specific
Epiphysis: - infection, chondroblastoma - geode, giant cell tumor (>30yo) Metaphysis: - osteochondroma, osteosarcoma - fibrosarcoma, non ossifying fibroma, chondromyxoid fibroma - aneurysmal bone cyst, simple bone cyst - chondrosarcoma (>30yo) Diaphysis - Ewing sarcoma (<30yo) - Fibrous dysplasia - Osteoblastoma Non specific - enchondroma - osteoid osteoma - mets
Common bone in
- finger
- calcaneum
- spine
- flat bones
Finger: enchondroma
Calcaneum: GCT
Spine: ABC, GCT, MM, Mets
Flat bones: chondrosarcoma, e wing sarcoma
types of periosteal reactions
solid, lamellated, spiculated, codmans
malignant bone tumors by age group
Young - osteosarcoma (metaphysis) - ewing (diaphysis) Older (all in metaphysis) - osteosarcoma - chondrosarcoma - multiple myeloma
possible primary sites for mets bone tumors
H&N: thyroid, NPC
thorax: breast, lung
abdo: kidney, GIT, prostate, testes
Osteosarcoma features
PEARL HARBOR
- paget disease*
- early age (10-20yo)
- around knee
- raised periosteum by tumor (sunburst)
- lace like architecture
- hyaline arteriosclerosis
- ALP increased
- retinoblastoma*
- boys predominantly
- OM is a differential
- Radiation*
*predisposing
Osteosarcoma RF
PRIMARY
- Paget
- Radiation
- Infarction of bone
- Male
- Alcohol, poor diet
- Retinoblastoma
- Young
Multiple myeloma
- what it is
- what clinical features
malignant b cell lymphoproliferative disorder of the marrow with plasma cells predominanting
Clinical features:
- generalised osteoporosis, lytic lesions throughout skeleton
- plasmacytoma
- blood abnormalities
- hyper Ca (resorption of bone)
- renal dysfunction
common lab/ investigation findings
- FBC: mild anemia (NCNC)
- high ESR
- RP: high Cr
- High Ca
- Bence jones proteins (urinalysis)
- Plasmacytosis with typical myeloma cells
- serum/ urine electrophoresis: monoclonal Ig band
- renal stones, gout, hyperuricemia
Difference between SBC and ABC
GCT?
SBC: fills medullary cavity, does not expand bone
ABC: at metaphysis, expansile
GCT: after fusion of physis, extends to subarticular/ articular surface (MUST), at epiphysis
mgx of osteosarcoma
- confirm disease (biopsy)
- stage disease: mets easily to lungs
- chemo + RT
- resection or amputation
tx for pathological fractures
open reduction
int fixation
