Giant Cell TumourJaffe 1940- AKA Osteoclastoma- Common- 18% of benign tumours- Occurs in 2° Oss centre ie epiphysis- Occ multicentric (rare) ~ MCQ- Can behave in malignant fashionF:M = 1.5:1 (most tumours M>F)=====Location- 50% at knee

Distal femurProximal tibia

- RemainderDistal radiusSacrumVert bodies like EG Cf ABC/OO which occur post

Bullough says include jaw or spine but look for pre-existing PAGETS=====Clinical- Us after skel mature- More common Females- 3% < epiphyseal closure- Peak incidence in 20's- Involved joint has:

Dull acheEffusionMuscle atrophy

- Pathol # common- Occur com ç Hyperparathyroidism

But Brown tumours mimick GCTSounds like bullshit I can’t find a reference for this- Can be pulsatile===XRXR- Us DxWell defined defect In Epiphysis & MetaphysisNO sclerosis around lesion- Subarticular ç extension into subchondral bone- May extend into articular cartilage

Unique ability ***- Min periosteal R'n- ± Cortical breach & ST extensionCT / MRI- Show cortical destruction & ST extensionBone Scan- Us shows inc uptake- Screens for other lesionsBloods- Ca++ & Se PO4 to rule out Brown's tumour- ESR inc ç OM & EG====PATH- Grossely resemble Scrambled eggs Two Cell Types1 Multinucleated Giant Cells - Sim to Osteoclasts2 Small Stromal Cells - ?The actual tumour ~ Enneking-yes are probably osteoblast derivativesGrade = Appearance of these - Background of fibrous tissue- N mitoses us seen- Areas of spont necrosis - Rare for B9 tumours- Giant Cell Ghosts

- Thin cortical shellAetiolTumour of stromal cellsGiant cells are osteoclast in nature and are reactiveStagingProposed by Enneking ?? CampanacciStage I Latent- 15% of patients- Asymptomatic- Sclerotic Rim- Inactive on bone scan- Histol benignStage II Active- 70% of patients- Symptomatic- Often have pathological fracture- Expanded cortex but no breakthru- Active on Bone Scan- Histol benign Stromal cellsStage III Aggressive-15% of patients- Symptomatic- Rapidly growing mass- Cortical peforation ç ST mass- Extensive activity on Bone Scan- Histol benign

Malignant- Rare form- Sarcomatous lesion contiguous ç Benign GCT Previously said 10% metastasizeBut many of these would now be called MFHFor it truly to be Giant cell have to see typical appearance of GCT in met1° malignant GCT better prognosis then malignant change in recurrenceDDxSynovial cyst of OA = GeodeOCD- Chondroblastoma/Clear Cell Sarc- Internal derangement of knee- EG- OM- Enchondroma- NOF- Unicameral CystMxStage- Bx us performed1 Excise the lesion 2 Sterilize the cavity3 Reconstruct the defectTraditional Rx- Bone graft & curettage- High recurrence rate (>35%)- Difficult to do intralesional excision without leaving tumour cells behind because of prox to articular cartilageModern Adjuvant Rx- Adjuvant Rx dev to dec recurrence1 Extended Curettage ç high speed burr & PMMA packing- Recommended- Works by thermal necrosis- Bone graft for 1cm under subchondral plate ? Beneficial- Waterpick+++2 Irrigation of Cavity ç Phenol- High comp rate

- OK if touch it with cotton bud3 CryoRx ç Liquid N2

- Imp principle is visualisation of whole cavity thru large cortical window & thorough curretage

Coffee Cup Theory

Wide Resection & Osteochondral allograft for :- Expendable bones- Recurrences- Unsalvagable bones

Grade III lesionsHence:Grade I & II- Extended currette ç high speed burr & bone graft &/or adjuvant PMMA- saucerisation is key word - ie to get good view & not miss any- long term studies suggest that <5mm subchondral then 30% chance of OA>10mm then no OAGrade III & Recurrence- Wide resection & Osteochondral allograftUnresectable- RadioRxOutcome- McDonald 1986 ~ 23% reccurrence 3 yrs- Histol °predictive ~ EnnekingEnneking Grade 1 = negligible recurrence

Grade 2 = 20%Grade 3 = 70%Grade 3 + adjuvant = 20%

Metastases- Lung metastases occur in 2%- Lesions slowly progress ie benign in nature- Us Rx ç surgical resection- Consider GCT Benign if Pulmonary Met histologically benign- Regular CXR in pts ç GCT

Dicko says need to know GCT well bc a lot of general ortho surgeons operate on GCTs and reasonable that we know how to do it well