Bone Tumours

Bone Tumours

·                 primary bone tumours are rare after 3rd decade

·                 metastases to bone are relatively common after 3rd decade

Diagnosis

·                 pain, swelling, rarely regional adenopathy

·                 routine x-ray

o       location (which bone, diaphysis, metaphysis, epiphysis)

o       size

o       lytic/lucent vs. scluotic

o       involvement (cortex, medulla, soft tissue)

o       matrix (radiolucent, radiodense or calcified)

o       periosteal reaction

o       margin (geographic n. permeative)

o       any pathological fracture

o       soft tissue swelling

·                 malignancy is suggested by rapid growth, warmth, tenderness, lack of sharp definition

·                 staging should include

o       bloodwork Including liver enzymes

o       CT chest

o       bone scan

o       bone biopsy

o       ––should be referred to specialized centre prior to biopsy

o       ––classified into benign, benign aggressive. and malignant

·                 MRl of affected bone

Benign Active Bone Tumours

1. Ostaold Osteoma

·                 peak incidence in 2nd and 3rd decades, M:F = 3:1

·                 small, round radiolucent nidus ( <1 cm) surrounded by dense bone

o       tibia and femur most common

·                 produces severe intermittent pain. mostly at night (diurnal prostaglandin production)

·                 characteristically relieved by NSAIDs

·                 not known to metastasize

2. Osteochondroma

·                 2nd and 3rd decades, M:F = 1.8:1

·                 45% ofall benign bone tumours

·                 metaphysis of long bone (distal ends of femur /proximal ends of humerus)

o       cartilage-capped bony spur on surface of bone ('"mushroom" on x-ray)

o       may be multiple (hereditary, autosomal dominant form) - higher risk of malignant change

·                 generally very slow growing and asymptomatic unless impinging on neurovascular structure

·                 malignant degeneration occurs in 1-2% (becomes painful or rapidly grows)

3. Enchondroma (Figure 54)

·                 2nd and 3rd decades

·                 50% occur in the small tubular bones of the hand and foot; others in femur, humerus, ribs

·                 benign cartilagenous growth, develops in medullary cavity

o       single/multiple enlarged rarefied areas in tubular bones

o       lytic lesion with sharp margination and central calcification

·                 malignant degeneration occurs in 1-296 (pain in absence of pathologic fracture is an important clue)

·                 not known to metastasize

4. Cystic Lesions

·                 includes unicameral/solitary bone cyst (most common), fibrous cortical defect

·                 children and young adults

·                 local pain. pathological fracture (50% presentations) or incldental detection

o       lytic translucent area on metaphyseal side of growth plate

o       cortex thinned/expanded; well defined lesion

·                 aspiration cystic fluid: green/yellow colour with high ALP

·                 treatment of unicameral bone cyst with steroid injections ± bone graft

Treatment

·                 treatment only necessary if symptomatic

·                 osteochondroma: resection

·                 cystic lesions: currettage and bone graft

Benign Aggressive Bona Tumours

Giant Cell Tumours/Aneurysmal Bone Cyst/Osteoblastoma (Figure 55)

·                 affects patients of skeletal maturity, peak 3rd decade

·                 found in the distal femur, proximal tibia, distal radius, sacrum, tarsal bones, spinal (osteoblastoma)

·                 cortex appears thinned, expanded; well-demarcated sclerotic margin; T2 MRI enhances fluid within lesion (hyper-intense signal)

·                 local tenderness and swelling

·                 15% recur within 2 years of surgery

·                 giant cell tumour occasionally metastasizes (1-2%)

Treatment

·                 intralesional curettage + bone graft or cement

·                 wide local excision of expendable bones

Malignant Bone Tumours

1. Osteosarcoma (Figure 56)

·                 most frequently diagnosed in 2nd decade of life (60%)

·                 history of Paget's disease radiation

·                 predilection fur distal femur (45%), proximal tibia (20%) and proximal hwnerus (15%)

o       invasive, variable histology; frequent metastases without treatment Oung most common)

·                 painful. poorly defined swelling. decreased ROM

·                 Hay shows Codman’s triangle (Figure 53)

o       ––characteristic periosteal elevation and spicule formation representing tumour extension into periosteum

o       destructive lesion in metaphysis may cross epiphyseal plate

·                 treatment: complete resection (limb salvage, rarely amputation), neo-adjuvant cbemo

·                 survival- 70%

2. Chondrosarcoma (Figure 57)

·                 primary (2/3 cases)

o       previous normal bone, patient over 40; expands into cortex to give pain, pathological fracture, flecks of calcification

·                 secondary (1/3 cases)

o       ––malignant degeneration of pre-existing cartilage tumour such as enchondroma or osteochondroma, younger age group and better prognosis than primary chondrosarcoma

·                 most commonly occurs in pelvis, femur, ribs, scapula, humerus (with metastasis to the hung)

·                 unresponsive to chemotherapy, treat with aggressive surgical resection+ reconstruction

3. Ewing's Sarcoma

·                 most occur between 5-20 years old

·                 florid periosteal reaction in diaphysis of long bone

o       moth-eaten appearance with periosteal lamellated pattern (onion-skinning)

·                 present with mild fever, anemia, leukocytosis and increased ESR/LDH

·                 metastases frequent without treatment

·                 treatment - resection, chemotherapy, radiation

·                 survival- 70%

4. Multiple Myeloma

·                 most common primary malignant tumour in adults

·                 90% occur in people >40 years old

·                 present with anemia, anorexia, renal failure, nephritis, increased ESR, bone pain (cardinal early symptom), compression fractures, hypercalcemia

·                 high incidence of infections (e.g. pyelonephritis/pneumonia)

·                 diagnosis

o       CT-guided biopsy of lytic lesions at multiple bony sites

o       serum/urine protein electrophoresis

·                 treatment chemotherapy, radiation, surgery for symptomatic lesions or impending fractures

5. Bone Metastases

·                 2/3 from breast or prostate; also consider thyroid, lung, kidney

·                 usually osteolytic; prostate occasionally osteoblastic

·                 bone scan for MSK involvement, MRI for spinal involvement may be helpful

·                 stabilization of impending fractures

o       internal fixation, IM rods

o       bone cement