Bone tumors Flashcards
Describe the layers of a long bone beginning at the external surface and moving towards the centre of the bone.
The layers of a long bone, beginning at the external surface are:
- Periosteum.
- Outer circumferential lamellae.
- Compact bone (Haversian systems).
- Inner circumferential lamellae.
- Endosteal surface of compact bone.
- Trabecular bone
What is an osteoma?
A benign tumour of osteoblast
What is neoplasia?
- New growth
- Growth that is unregulated, clonal and irreversible.
- Can be benign or malignant
Overview of benign tumours
Bone forming:
- osteoma
- osteoid osteoma
- osteoblastoma
Cartilage forming”
- chondroma
- osteochondroma
Other:
- Giant cell tumour of bone
Overview of malignant tumour
Bone forming:
- Osteosarcoma- malignant tumour of osteoblasts
Cartilage forming:
- Chondrosarcoma- malignant tumour of chondrocytes
Other:
Ewing sarcoma
- Multiple myeloma
- Metastatic
- Malignancy
Describe osteochondroma: what is it, what it looks like,
epidemiology, aetiology, presentation, radiological findings, management
Composed of bone w// overlying cartilage cap
- lesions can be pedunculate (on a stalk) or sessile (flat)
- pedunculate lesions point away from nearest joint
What is looks like:
https://www.notion.so/Pathology-505a8e432c43476f836c6ea43f29e452
Epidemiology;
- Common in benign bone tumor
- M: F = 3:1
- commonly diagnosed in under 30s
Aetiology:
- not fully understood- loss of function mutations have been identified in tumour suppressor genes EXT1/2 & 3
Presentation:
- Asymptomatic- so incidental finding
- Can cause symptoms due to fracture, impingement of nerves e.g. perineal nerve= footdrop
- Multiple lesions more likely to present at earlier age e/ symptoms due to growth restrictions
- Commonly affects metaphysics of long bones ((femur, humerus)
- a cap of hyaline cartilage which is undergoing endochondral ossification merges with the underlying trabecular bone.
Radiological finding:
- Continuity of cortex & medullary cavity of the lesion w/ that of parent bone
- https://www.notion.so/Pathology-505a8e432c43476f836c6ea43f29e452
Mangement:
- If asymptomatic, watch & wait w/ x-ray observation- growth often ceases after skeletal maturity
- Surgical excision is performed for symptomatic lesions- usually curative if all cartilagenous cap is removed
Describe osteoid osteoma: what it looks like,
epidemiology, aetiology, presentation, radiological findings, management
Benign bone forming neoplasm of osteoblasts that is characterised by a limited growth potential
- lesion is <2cm in size
- usually solitary
- appears as a discrete oval or round mass of reddish-brown tissue surrounded by sclerotic bone w/in cortex of bone
- Malignant change is rare
What it looks like:
https://www.notion.so/Pathology-505a8e432c43476f836c6ea43f29e452
- lucency in the cortex w/ a surrounding rim of reactive bone formation
Epidemiology:
- M:F = 2:1
Aetiology:
- Rare cases of familial recurrence
Presentation:
- Night pain
- Tenderness
- Relieved by NSAID & aspirin
- Likely due to prostaglandins E2 produced by neoplastic osteoblasts
- Affects cortex of diaphysis or metaphysis of long bones
- Usually affects lower limb
Radiological findings:
- Imaging (XR) shows well-defined central radiolucent nidus surrounded by dense sclerosis
- nidus has a sharp margin which interfaces w/ a surrounding rim of mature bone.
- In intra-medullary lesions, which are not characterised by sclerosis- MRI may be needed to evaluate further
Mangamanet:
- CT guided radial frequency ablation (minimally invasive)
- Complete surgical excision of nidus (curative)
Osteoid osteoma vs osteoblastoma
They have similar histologic features
but differ clinically & radiographically.
Osteoblastoma is >2 cm & involves the posterior components of the vertebrae (laminae and pedicles) more frequently.
Osteoblastoma- pain is unresponsive to NSAIDs &
tumour usually does not induce a marked bony reaction.
- usually surgically curetted or excised.
Osteoid Ostoma: Ooh that’s better – relieved by NSAIDS
Osteoblastoma: Blasted by pain – not relieved by NSAID
Describe giant cell tumour: what it looks like,
epidemiology, presentation, radiological findings, management, prognosis
A locally aggressive & rarely metastasising neoplasm
- Multi-nucleated osteoclast type giant cells
- Tumours are red-brown masses that frequently undergo cystic degeneration
- Tumour lacks bone or cartilage, consisting of numerous osteoclast- type giant cells
- >40 nuclei w/ uniform, oval mononuclear tumour cells in-between
What it looks like:
Epidemiology:
- M:F = 1:14
- Median age of 35y
Presentation:
- Presents w/ pain, swelling & reduced ROM
- similar symptoms to arthritis
- Usually occurs in metaphase & epiphysis of long bones in skeletally mature patients i.e. adults
- Commonly affects femur, tibia & radius
Radiological findings:
- x-ray- soap bubble lytic lesion at end of long bone
- cortex is often destroyed & covered in thin shell of reactive bone
https://www.notion.so/Pathology-505a8e432c43476f836c6ea43f29e452
Management:
- Surgical- amputation, joint replacement, curettage (defect filled w/ cement)
Prognosis:
- Local recurrence is high- 25-50%
- Tumour rarely acts in malignant way & pulomar metastases can occur in 2%
Describe Osteosarcoma: what is it, what it looks like,
epidemiology, presentation, risk factors, radiological findings, management, prognosis
Malignant proliferation of osteoblasts
- Often fills medullary cavity of metaphysis & proximal diaphysis of long bones
- Macroscopical tumour is tan-white
- Often infiltrates through cortex, lifts periosteum & forms a soft tissue mass
- Microscopically there’s a lace-like pattern of bone
- Tumour cells vary in size & shape
- Have large hyper chromatic nuclei & multiple mitoses
What it looks like:
https://www.notion.so/Pathology-505a8e432c43476f836c6ea43f29e452
Epidemiology:
- Most common malignant bone tumour in children
- M:F- 1.6:1
- 2 peaks of incidence- 1st= 2nd & 3rd decades (correlated w/ pubertal growth spurt. 2nd= 7th & 8th decades (secondary toe Paget’s disease, previous radiotherapy)
Risk factors:
- Paget’s disease
- previous history
- radio/ chemotherapy
- Familial retinoblastoma syndrome- an inheritable mutation in the retinoblastoma tumour suppressor gene which predisposes the patient to develop eye tumours called retinoblastomas & osteosarcoma.
Aetiology:
- risk factor- mutations of tumour suppressor genes - p53, Rb & CDKN2A (encodes p16 & p14. p16 is a negative regulator of cyclin-dependent kinases & p14 augments p53 function).
- patients w/ mutation in RB have 1000-fold increased risk of osteosarcoma
- there are 2 oncogenes which are over expressed in low-grade osteosarcoma- MDM2- inhibits p53 & CDK4- inhibits Rb
Presentation:
- Pain
- swelling
- limping / limited ROM
Radiological findings:
- x-ray shows combination of bone destruction & formation- w/ infiltrative margins
- Soft tissue calcification produces sun burst appearance & lifting of periosteum called codmans triangle due to tumour breaking through cortex
Mangament:
- Surgical resection of all gross disease in conjunction w/ systemic chemotherapy to control micro-metastatic disease disease
Prognosis:
- 5 year survival in 70% for localised osteosarcoma
- patients w/ metastatic or recurrent disease- survival rate= 20%
What is Chondrosarcoma: what does it look like, epidemiology, aetiology, presentation, radiological findings, management, prognosis.
Malignant tumour that produces cartilage
- can be primary (arising w/out precursor) or secondary (from pre-existing e.g. osteochondroma)
- Macroscopically nodules of hyaline & myxoid cartilage seen permeating throughout medullary cavity, growing through cortex & forming well-circumscribed soft tissue mass
- Microscopically there are malignant chondrocytes which show varying mitotic activity (binucleate forms.)- nuclei are much larger, darker & more irregular
What it looks like:
https://www.notion.so/Pathology-505a8e432c43476f836c6ea43f29e452
Epidemiology:
- 2nd most common malignant primary bone tumor
- occurs in middle age to older adults
- more common in men
Aetiology:
- unknown for primary chondrosarcoma
- malignant transformation from benign precursor e.g. osteochondroma
Presentation:
- arise in skeleton especially pelvis, shoulder 7 ribs
- chondrosarcomas present as painful progressively enlarging masses
Radiological finding:
- XR shows calcified cartilage as flocculent or popcorn like may destroy cortex & form soft tissue masses
- Suspicion raised from secondary chondrosarcoma if cartilaginous cap >1.5cm thick in osteochondroma
Management:
- Conventional chondrosarcoma = wide surgical excision
- Mesenchymal & differentiated tumours are excised & are treated w/ chemotherapy
Prognosis:
- low grade tumours rarely metastasise- 5 year survival for 80%
- high grade often metastasise to lungs- less than 5 year survival for 50%
What is Ewing Sarcoma- description, what it looks like, epidemiology, aetiology, presentation, radiological findings, management, prognosis.
Malignant proliferation of small round blue cells derived from neuroectoderm which typically arises in medullary cavity in diaphysis of long bones:
- Macroscopically- tumour is soft, tan white, contains areas of haemorrhage & necrosis
- Microscopically, there are solid sheets of small, uniform hyperchromatic (dark) cells w/ high nuclear to cytoplasmoic ratios (like lymphocytes)
What it looks like:
- Onion skin reaction
- Sunburst or hair-on-end reaction
Epidemiology:
- More common in males
- 80 < 20 y of age
Aetiology:
- Contain a balanced translocation generating in-frame fusion of EWSR1 gene on chromosome 22 to FLI1 gene on chromosome 11
Presentation:
- Localised, painful mass or swelling
- most common in long bones of arms & legs
Radiological finding:
- X-ray- uneven tumour growth produces onion-skin. periosteal reaction (a pattern of 1 or more concentric shells of new bone over lesion
- A steady tumour growth Sharpe’s fibres (fibres that connect periosteum to bone) become stretched out perpeniduclar to bone & ossify- produces sunburst old hair-on-end periosteal reaction
- moth-eaten, permeative, destructive lucent lesions in the diaphysis of long bones, w/ large soft tissue component, w/out osteoid matrix
Mangement:
- 1st line of treatment- neoadjuvant chemotherapy & surgery
- Radiotherapy for inaccessible sits- less effective
prognosis:
- 5 y survival is 60& in localised & 20% in metastatic disease
What is onion skin reaction? What does it look like
In Ewing sarcoma, tumour is fast growing & periosteum cannot produce new bone as fast as lesion is growing
If lesion grows unevenly it fits & starts, then periosteum may have time to lay down a thing shell of calcified new bone before the lesion takes off again on its next growth spurt
May result in pattern of 1 or more concentric shells of new bone over the lesion i.e. onion skill
What does it look like:
https://www.notion.so/Pathology-505a8e432c43476f836c6ea43f29e452
What is hair-on-end reaction (sunburst)? What does it look like?
If lesion grows rapidly but steadily, periosteum will not have enough time to lay down even a thin shell of bone- so pattern will appear different
Tiny fibres that connect periosteum to bone (Sharpey’s fibres) become stretched out perpendicular to bone
When these fibers ossify, they produce a pattern called “sunburst” or “hair-on-end” periosteal reaction, depending of how much of the bone is involved by the process.
What does it look like:
https://www.notion.so/Pathology-505a8e432c43476f836c6ea43f29e452
What is Metastatic carcinoma: what does it look like, epidemiology, pathophysiology, presentation, management, prognosis
What may it look like:
- https://www.notion.so/Pathology-505a8e432c43476f836c6ea43f29e452
Epidemiology:
- Outnumber primary bone cancers
- Most common site of origin- i.e. where primary tumour came from
- Adults- breast, lung, thyroid
- Children- Neuroblastoma, wills tumour
Pathophysiology- pathway of tumour spread to bone includes:
- Direct extension
- Haematogenous
- Lymphatic spread (most common)
- Intraspinal seeding (via the Batson plexus of veins).
- Tumour cells can secrete substances that increase osteoclastic activity.
- e.g. prostaglandins, cytokines and PTH-like peptides
- These substances up-regulate RANKL on osteoblasts producing lytic lesions
- Or they can produce substances that increase osteoblastic bone formation
- e.g. WNT proteins producing sclerotic lesions.
Presentation:
- multifocal & involve the axial skeleton especially the vertebral column.
Mangagement:
- Chemo/radiotherapy
- Bisphosphonates
- Surgery to stabilise pathological fractures
Prognosis
- poor outcome
