Bone Tumours Flashcards
Where and when do primary and secondary ossification centres appear in long bone?
Primary - centre of the diaphysis during intrauterine life.
Secondary - each epiphyseal end sometime after birth.
How do bone tumours typically present?
- Pain
- Unexplained limb pain >1 month
- Pain at night - Swelling
- Pathological fracture
- Incidental finding - most primaries
What are the 3 forewarning signs of malignancy on X-ray?
- Cortical destruction
- Periosteal reaction
- Fuzzy line outside of cortex
- Also seen with # or infection - Zone of transition
- Sclerotic margin = narrow zone
- Diffuse margin - more aggressive
List 6 clinical indicators of malignancy?
- Pain (>1 month, at night)
- Swelling
- Tenderness
- Warmth
- X-ray changes (3 signs)
- Rapid growth of a lesion
What investigations are indicated if bone malignancy is suspected?
- X-ray
- Bone scans
- CT
- MRI
- ESR - raised
- ALP - raised
- Biopsy
Refer to specialist centre early
Recite the mnemonic for benign bone tumours
ABC FFG OO
Aneurysmal bone cyst Bone cyst - Simple, unicameral or solitary Chondroma - Aka endrochondroma Fibrous cortical defect - Aka nonossifying fibroma Fibrous dysplasia Giant cell tumour Osteochondroma Osteoid osteoma
Expansile cysts that usually affect under 30s. Patients present with pain. MRI shows multiple fluid levels.
Aneurysmal bone cyst (benign tumour)
What is the pathognomonic sign for aneurysmal bone cysts, as seen on MRI?
Multiple fluid levels
How are symptomatic aneurysmal bone cysts treated?
Curette out cyst and fill with bone graft.
In which bones and in whom do simple bone cysts most commonly occur?
Proximal humerus and femur.
Young patients.
Usually asymptomatic.
When might you see the ‘fallen fragment sign’?
Specific radiological sign for a unicameral bone cyst with pathological fracture. Part of the thinned cortex ‘falls’ into the fluid-filled cyst.
Differentiate between Ollier’s disease, Maffucci’s syndrome and metachondromatosis.
Multiple enchondromas present in 3 disorders: Ollier disease - Sporadic (more common) - Unilateral distribution Maffucci's syndrome - Sporadic - Associated with hemangiomas Metachondromatosis - Autosomal-dominant - Both multiple osteochondromas and enchondromas.
What are (endo)chrondromas and which bones are most commonly affected?
The most common benign tumours of hyaline cartilage
Commonest site: phalanges. Can affect other long bones.
A 43 year-old man presents with ongoing pain and swelling in his hands and feet. X-ray findings reveal cystic lesions of the phalanges. Which condition is it important to exclude?
Low-grade chondrosarcoma - may develop from benign cystic lesions (chondromas)
What is a nonossifying fibroma and how does it typically present?
Aka fibrous cortical defect.
- Benign defect of cortex
- Common: incidental finding on X-ray in 20% of children
- Nonpainful
- Usually affects metaphysis
- Usually spontaneously regress
- Rarely seen after age 30
Differentiate between monostotic and polystotic fibrous dysplasias
Fibrous dysplasia = areas of bone are replaced by fibrous tissue.
Monostotic = localised
- Solitary segment affected
- More common (70-80%)
- Unknown cause
- Incidental X-ray finding or presents as pathological # with pain
Polystotic = generalised
- 20-30%, several bones affected
- Presentation: progressive deformity (bending, enlargement), pain and pathological fracture
- X-ray: ground glass or smokey
- Elephant man?!
What is McCune-Albright syndrome?
A rare condition in which polyostotic fibrous dysplasia occurs in association with café au lait spots and (in females) precocious puberty (endocrinopathies).
In whom and in which bone(s) are giant cell tumours most commonly seen?
Occur in young adults (always after fusion of growth plate) usually around knee (lower femur or upper tibia) and always abut the articular surface.
Which is the commonest tumour of the bone?
Osteochondroma - aka “exostosis”, a cartilage-capped outgrowth. Arise from metaphysis, especially about knee. M>F (3:1)
A patient presents with a bony lump. X-ray shows a cauliflower-shaped projection from bone that is smaller than the size to touch. What is the most likely diagnosis?
Osteochondroma - if symptomatic, excise tumour.
Chondrosarcoma - if it changes in size after skeletal maturity.
A 20 year old patient presents with ongoing leg pain which is relieved by aspirin. X-ray shows a small radiolucent area surrounded by dense sclerosis which appears as a hot spot on a bone scan. What is the most likely diagnosis and how would you treat?
Osteoid osteoma - a benign tumour (
How does an osteoblastoma differ to an osteoid osteoma?
An uncommon primary bone tumour with clinical and histological similarities to osteoid osteoma, but larger (2-6 cm). Usually benign and related to spine.
In whom do osteosarcomas most commonly occur?
Males > females (3:1)
Primary: adolescents (under 20)
Secondary: over 50s (due to Paget’s disease)
What is the main symptom of osteosarcoma?
Pain, especially nocturnal
+/- local tenderness
What are the radiological features of osteosarcoma?
X-ray:
- Metaphyseal, translucent, destructive lesion
- Expands through cortex, lifts, periosteum
- Codman’s triangle
- ‘Sun-ray’ appearance
What is Codman’s triangle?
Radiographic feature:
Triangular area of new subperiosteal bone, created when a lesion raises the periosteum away from the bone
What are ‘sun-ray’ and ‘sunburst’ appearances caused by?
Sun-ray appearance occurs with rapidly-growing lesions
- Streak of calcification
- Periosteum has no time to lay down thin shell of bone
- Sharpey’s fibers stretch out, perpendicular to the bone
When these fibres ossify, they produce a pattern sometimes called “sunburst” periosteal reaction
How are malignant bone tumours treated and what is their prognosis?
- Chemotherapy - except chondrosarcomas
- Resection
- Amputation
- Or wide local excision (allograft or prosthesis)
Five-year survival
- Osteosarcoma: 60%
- Chondrosarcoma: 50%
Name the rare malignant tumour that arises from bone marrow, usually in young patients.
Ewing’s sarcoma - boys > girls
True or false: most Ewing’s sarcomas occur in diaphysis of long bones
True - especially femur, also tibia and humerus
True or false: osteosarcomas tend to be metaphyseal
True
A 25 year-old patient presents with a painful pelvic swelling that is warm and tender. X-ray shows an onion-skin appearance. What is the diagnosis?
Ewing’s sarcoma - occasionally misdiagnosed as osteomyelitis
What causes an ‘onion skin’ appearance on X-ray?
Several layers of periosteal new bone around destructive lesion - seen in Ewing’s sarcoma
A 45 year-old patient presents with a painful swelling in pelvis. X-ray shows an expanding radiolucent lesion with flecks of calcification. What is the diagnosis?
Chondrosarcoma - usually affects older patients (40+)
Describe the two types of chondroma/chondrosarcoma
- Subperiosteal chondroma: arises on surface of bone
- Sometimes in cartilage-covered cap of osteochondroma - Endochondroma: arises within medulla of bone
- Either slow-growing malignancy or benign chondroma that becomes malignant
True or false: chondrosarcomas tend to be treated with chemotherapy before excision
False - Rx by excision or amputation since they metastasise late
Which malignant tumours are more common in younger patients (under 30)?
- Osteosarcoma
2. Ewing’s sarcoma
Which malignant tumours are more common in older patients (over 40)?
- Chondrosarcoma
- Myeloma
- Metastases
Which cancers most commonly metastasise to bone?
‘Bone Tumours are Rarely Bony Primaries’
- Breast
- Thyroid
- Renal
- Bronchus
- Prostate
True or false: most metastases are osteoclerotic lesions
False - majority are lytic lesions
Exception: prostate - usually osteosclerotic
However, breast and thyroid are sometimes osteosclerotic
Which bones do secondaries tend to metastasise to?
Axial skeleton (red marrow) - Spine, pelvis, ribs, proximal and of long bones
How do secondary bone tumours tend to present?
- Local pain
2. Pathological fracture
How are pathological fractures treated?
Internal fixation - as they tend not to heal
How do secondary bone tumour tend to be treated?
- If local - radiotherapy
2. If multiple - palliative (poor prognosis)
True or false: most benign lesions are seen <30 years of age
True
True or false: a new bone tumour in the elderly is more likely to be malignant
True
What is the best test for diagnosis and staging of bone tumours?
Dx: X-ray
Staging: CT or MRI
Histology grade
- Most important prognostic feature of sarcomas
- Essential for staging of most bone tumour types
What are the most common benign lesions in the under 20s?
ABC FFG OO - Endochondroma - Giant cell tumour \+ Osteoblastoma \+ Chondroblastoma \+ Chondromyxoid fibroma \+ Eosinophilic granuloma
What are the most common malignant tumours in the under 20’s?
- Osteosarcoma
- Ewing’s sarcoma
- Metastatic neuroblastoma
- Leukaemic involvement
In younger patients think osteosarcoma or Ewing’s sarcoma!
What are the most common benign lesions in 21-40 year olds?
- Endochondroma
2. Giant cell tumour
What are the most common malignant tumours in 21-40 year olds?
Chondrosarcoma
In older patients think chondrosarcoma, myeloma and mets!
What is the most common benign lesion in the over 40s and in which bones does it commonly arise?
Osteoma - facial bones, skull
What are the most common malignant lesions in the over 40s?
- Metastatic tumours
- Myeloma
- Leukaemic involvement
- Chondrosarcoma
- Osteosarcoma (Paget’s associated)
- Malignant fibrous histiocytoma
- Chordoma
In older patients think chondrosarcoma, myeloma and mets!
True or false: most secondary bone tumours have favoured sites within long bone
False - this is true of primaries
Diaphyseal cortical lesion
Osteoid osteoma
Diaphyseal intramedullary lesion
- Fibrous dysplasia
- Endochondroma
- Ewing’s sarcoma
- Lymphoma
- Myeloma
Metaphyseal cortical lesion
- Non-ossifying fibroma
2. Osteoid osteoma
Metaphyseal intramedullary lesions
- Osteosarcoma
- Chondrosarcoma
- Fibrosarcoma
- Osteoblastoma
- Endochondroma
- Fibrous dysplasia
- Simple bone cyst
- Aneurysmal bone cyst
Epiphyseal lesions
- Chondroblastoma - rare, open growth plates
2. Giant cell tumour - closed growth plates
Metaphyseal exostosis
Osteochondroma
What are the commonest sites for an osteosarcoma?
Primary: locally invasive (metaphysis)
- Around knee (distal femur/proximal tibia)
- Proximal humerus
Secondary: femur, humerus, pelvis
Where do osteosarcomas commonly metastasise to?
Often metastasises to lung via blood
Where do chondrosarcomas commonly arise and where do they spread to?
Common sites: central portions of skeleton:
- Pelvis, proximal femur, ribs, sternum, shoulder girdle
Spreads to lungs and skeleton
What is a giant cell tumour?
Uncommon, benign bone tumour. Contains a profusion of multinucleate osteoclast type giant cells. Usually benign but may become locally aggressive and metastasise. Arises during 5th decade. Female predominance
In which bones are osteoblastomas commonly found?
Vertebral column
What are Homer-Wright rosettes?
Small round blue cells arranged in rosettes with a neurofibrillar centre - pathobiologic marker for Ewing’s sarcoma
What is a chordoma?
A rare slow-growing neoplasm thought to arise from cellular remnants of the notochord. Chordomas can arise from bone in the skull base and anywhere along the spine (neuraxis).
Commonest locations:
1. Cranially at the clivus
2. Sacrum
