HISTO: Bone Tumours Flashcards
How common are bone tumours? When are primary malignant bone tumours more common?
- Very rare
- malignant tumours 60x less common than lung cancer
- primary malignant bone tumours most common in children and young adults
Femur metaphysis
What type of site predilection is present in bone tumours?
Occur around the knee most commonly
BUT different tumours have different site and age predilection
What are the clinical features of bone tumours?
- pain
- swelling,
- deformity,
- fracture
Must ask about:
- age, site, duration, ?hx of trauma
- ?multiple lesions, ?associated disease
How do you diagnose bone tumours?
XR:
- Evaluate site, size, margin
- ?solitary or multiple, ?soft tissue extension
- ?associated disease or fracture
Biopsy
- Needle biopsy preferred option
- Performed by radiologist usually with Jamshidi needle
- +/- US or CT guidance
- Open biopsy for sclerotic or inaccessible lesions
- Imprint (cytology) preparations are very useful
- Optimal treatment is early referral to specialist centre
Malignant - trabecular bone is irregular here, there is a mix of cartilagenous tissue which shouldn’t usually be there
Normal bone marrow is shown below
List some bone tumour-like conditions.
- Fibrous dysplasia
- Metaphyseal fibrous cortical defect/non-ossifying fibroma
- Reparative giant cell granuloma
- Ossifying fibroma
- Simple bone cyst
List 5 benign bone tumours.
How common is fibrous dysplasia? Who is most affected?
- F>M
- Up to age 30yrs
- Polyostotic disease can be associated with endocrine problems and rough border café au lait spots on skin (McCune Albright syndrome)
Which genetic mutation may be present in fibrous dysplasia?
Somatic mutation in guanine-nucleotide binding protein (G-protein). (GNAS mutation chr 20 q13)
Which syndrome can fibrous dysplasia be associated with?
McCune Albright syndrome
Polyostotic disease can be associated with endocrine problems and rough border café au lait spots on skin
What % of fibrous dysplasia undergoes malignant transformation?
<1%
What is shown?
Soap bubble osteolysis
Characteristic feature of fibrous dysplasia is that it will always be present in more than 1 bone whereas primary bone scarcoma would not, unless metastasis.
What are the histological features of fibrous dysplasia shown here?
Marrow replaced by fibrous stroma
Rounded and curved trabecular bone - called “Chinese letters”
With benign diagnosis of fibrous dysplasia, what is the treatment?
Resection with narrow margins can be used if cosmetically unacceptable
No aggressive treatment necessary
What deformity is shown here? What is the consequence? (left femur on image)
Fibrous dysplasia causing Shepherd’s crook deformity
Bone is weak and cystic so predisposed to fractures
What are the commonest sites of osteochondromas?
What is a feature of this osteochondroma?
This bone outgrowth has a stalk or stem that sticks out from the normal bone. If the tumor has a stalk, the structure is called pedunculated.
What are the histological features of osteochondromas?
Mimic tubular bone and will have a cartilagenous surface overlying the cortical and trabecular bone
What is an enchondroma? What are the most common sites?
Enchondroma - cartilagenous proliferation within the bone
Majority in the hands, some in feet, less in long bones
What is this sign in enchondroma?
Popcorn calcification
What is shown?
Enchondroma - well circumscribed proliferation so can use a narrow excision (this is a benign condition)
Is this tumour benign or malignant?
Benign - but can be locally aggressive. Features include that it is well demarcated and although it has gone through cortex it is still not leaving surface.
This is an example of a giant cell tumour (borderline malignancy)
What is the site of most giant cell tumours?
Epiphysis with metaphyseal extension
Ends of long bones, knees most affected
Who is most affected by giant cell tumours?
20-40yo
F>M
Are the XR and histological features of giant cell tumours?
XR: lytic
Histo: osteoclasts on background of spindle/ovoid cells, locally aggressive, may recuur and can metastasise
NB: this is borderline malignancy
What are the giant cells in giant cell tumours of bone?
Sheets of osteoclasts
What are the most common sited of osteosarcomas? What ages are affected and what sex?
Peak in adolescence (75% <20yo)
60% occur in knee
What sign of osteosarcoma is seen on this XR?
Codman’s triangle (periosteal)
Sclerotic and lytic lesions are seen. There is invasion of the soft tissue which has pushed the periosteum off.
What ages are most affected by chondrosarcoma? Where do they usually occur?
Age: 40y and over
Site: pelvis, axial skeleton, prox femur, prox tibia
Is this the arm or leg?
Arm
Is this benign or malignant?
Chondrosarcoma so malignant
What ages are most affected by Ewing’s? What sites are most affected?
Age: usually < 20y (80%)
Site: diaphysis/metaphysis of long bones, pelvis
What are the XR and histological features of Ewing’s sarcoma?
X-ray: onion skinning of periosteum, lytic +/- sclerosis (shown below to be affecting the fibula and soft tissue)
Histo: sheets of small round cells
Immunostaining can be used to exclude other diagnoses and to confirm Ewing’s sarcoma.
NG: ES will be positive for neuroendocrine markers (S100 and synaptophysin) and CD99 but nothing else.
What type of soft tissue tumour is this?
Liposarcoma/myxoid
What type of soft tissue tumour is shown?
Spindle cell sarcoma
What type of soft tissue tumour is shown?
Pleomorphic tumour
Why is this called a “biphasic tumour”?
Synovial sarcomas have epithelial and spindle cell areas.
