Tumours of MSK system Flashcards
Epidemiology of bone tumours
Sarcoma of Bone account for 0.2% of all malignancies
Approx 500 diagnosed in the UK every year
However represent 4% of all malignancies in Children <14 years
Slight higher incidence in males (13:10)
Approx 3275 new cases per year in UK
Almost equal distribution between Males and Females (51:49)
Typical patient history for bone tumour
Presenting Complaint:
?Mass
?Pain
?Loss of Function
History of Presenting Complaint:
Duration of symptoms, including full Pain / Mass history
How issue came to patient’s attention
Past Medical History and Medication History
Family History
Social History – what is their current level of function?
Red flag signs in history
Rest pain
Night pain
Lump present – tender, enlarging, deep to fascia, above 5cm in diameter
Loss of function
Neurological symptoms
Unwell / Weight loss
Examination of patient
Look, Feel, Move
Assess function of a joint/limb:
Range of motion
Neurovascular status
Assess any masses
Scars
Skin lesions
sensations
Reflexes
Initial investigations
Blood tests – FBC, U+E, Ca2+, Alk Phos
Plain Xrays
Ultrasound
CT Scan
MRI Scan
Bone scan
Raised CRP and ESR
Urine
CT scan and tumours
Better for assessing bone quality, as well as solid tumours
Staging CT of Chest / Abdo / Pelvis essential if suspect metastases
MRI scan
Better for assessing reactive changes of soft tissue / bone marrow
Recent studies assessed full-body MRI to look for metastases
T1 imaging: anatomy
T2 imaging: pathology
Soft tissue masses
Skip lesions
Bone scan
Better for assessing reactive changes of soft tissue / bone marrow
Recent studies assessed full-body MRI to look for metastases
Plain x ray
Look to see what the lesion is doing to the bone and vise-versa
Definition / Bone density / Zone of Transition / Periosteal reaction
Osteoblastoma (looks dark) vs Osteosarcoma (looks bright white)
Plain x ray can show the location of the tumour in the bone… what are the locations in bone?
Epiphysis
Physis
Metaphysis
Diaphysis
Central/Cortical
A plain x ray shows the zone of transition what are they
Narrow - good
Wide - bad
Plain x rays can show the matrix, what is a matrix
Represents the extracellular matrix produced by tumor cells
Depends upon cellular lineage of progenitor cells
Fibrous – ground glass
Osteoid – Cumulus cloud
Chondroid – Popcorn
Plain x ray can show cortical involvement such as
Scalloping
Cortical thinning
Expansile
Ultrasound
Chepa and quick
Real time assessment
Differential normal vs abnormal, solid vs cystic
Staging: Grading of Malignant Tumours
Enneking system:
G0 = Histologically Benign
Well Differentiated i.e. resemble cell of origin
Low mitotic count
G1 = Low Grade Malignant
Moderate differentiation; Few mitoses
Local spread only. Low risk of metastasis
G2 = High Grade Malignant
Poorly differentiated; Frequent mitoses
High risk of metastasis
Enneking classification Grade 1
Latent
Well defined margin. Grows slowly then stops
May heal spontaneously and very low risk of recurrence
Enneking classification Grade 2
Active
Progressive growth limited by natural barriers
Well defined margin but may expand and thin cortical bone (e.g. ABC)
Negligible recurrence after marginal resection
Enneking classification Grade 3
Aggressive
Growth not limited by natural barriers (e.g. GCT)
Metastasis present in 5% patients
High recurrence following marginal resection (extended resection therefore needed)
Enneking classification: T1 AND T2
T1 - intracompartmental
T2 - extracompartmental
Guide to naming tumours prefix
Osteo… = Bone
Chondro… = Cartilage
Rhabdomyo… = Skeletal Muscle
Lipo… = Fat
Guide to naming tumours suffix
oma = Benign tumour
…sarcoma = Malignant connective tissue tumour
…carcinoma = Malignant epithelial/endothelial tumour
…blastoma = (Malignant) Tumour of embryonic cells
Outliers to naming tumours
Tumours may have an eponymous name (e.g. Ewing’s)
If the Tissue of Origin is unclear, the tumour may be described by its cellular appearance
Or, especially in soft tissue sarcoma, may come under the term
Where do bone tumours present
Osteosarcoma - knee (distal femur, proximal tibia)
Parosteal osteosarcoma - distal femur (posterior cortex)
Chondrosarcoma – pelvis
Giant cell tumors – knee
Chordoma – sacrum
Adamantinoma - tibia
Bone cysts usually found in children
Unicameral Bone Cyst (UBC)
Aneurysmal Bone Cyst (ABC)
Fibrous dysplasia
Eosinophlic granuloma (EG)
Intra-osseous lipoma (rare
Destructive lesions in young adults
Osteosarcoma
Ewings
Infection
Giant Cell Tumour (GCT)
ABC
Destructive lesions in those >50
Osteosarcoma
Chondrosarcoma
Metastasis
Myeloma/Lymphoma
Giant cell tumour
Infection
Bone Tumours
Benign
Osteoid Osteoma
Osteoblastoma
Osteochondroma
Malignant
Osteosarcoma
Fibrous tumours
Benign
Fibrous Dysplasia
Non-ossifying Fibroma
Malignant
Fibrosarcoma
Cartilage tumours
Benign
Enchondroma
Chondroblastoma
Malignant
Chondrosarcoma
Cystic tumours
Unicameral bone cyst
Aneurysmal bone cyst
Unknown aetiology tumours
Giant cell tumour
Ewing Tumour
Adamatinoma
Osteoid osteoma
Benign, bone-forming lesion in young pts
Localised pain and self-limiting (<7yrs).
Produces high levels Prostaglandin E2
Proximal femur, Tibial diaphysis, Spine
Xray – Active reactive bone + nidus (5-10mm)
Best appreciated on CT
Management for osteoid osteoma
Medical Mx: NSAID’s (50% successful)
Surgical Mx: Radiofrequency Ablation/ En-bloc Resection
Osteoblastoma
A rare bone producing tumour
The “big brother” of osteoid osteoma > 2cm
M:F= 3:1
Presentation = pain, not self-limiting
Locations: Spine, proximal humerus, sacrum
Spine lesions can present with neurology
X-rays: Bone destruction surrounded by reactive new bone.
Histology of osteobastoma
Interlacing trabeculae + loose fibrovascular stroma
Treatment for osteoblastoma
Excision with at least a marginal line of excision
Osteochondroma
Metaphyseal lesion, covered by cartilage cap, grows away from growth plate and stops growing after puberty
PC: painless lump
Males > females
May have a narrow stalk (pedunculated), or broad base (sessile)
Treatment for osteochondroma
Surgical excision if symptomatic.
Chance of malignant change: less than 1%.
What is osteosarcoma
Spindle cell neoplasms that produce osteoid
Different types of osteosarcoma
Intramedullary osteosarcoma (high grade)
Parosteal osteosarcoma (low grade)
Periosteal sarcoma (high grade)
Telangiectatic osteosarcoma
Secondary osteosarcomas
Paget’s, Post-Radiation, Fibrous Dysplasia
What are osteosarcomas assosciated with?
Also associated with Chondrosarcoma and STS
High-grade intramedullary osteosarcoma
“Classic” osteosarcoma
Most common type
Location: knee, proximal humerus, proximal femur
Age: children, young adults
90% are high grade and penetrate the cortex early forming a soft tissue mass (IIB lesion)
10-20% have pulmonary mets
X-rays: bone formation with bone destruction
MRI useful for staging
Pagets disease
Older population only. Pagets present in 0.7-0.9% population, hence this is rare
Median age 64yrs for onset. High risk for pulmonary metastasis
Irradiation
60-70% survival for extremity lesions, 27% axial lesions
Children treated with high dose radiotherapy at greatest risk
Tend to be high-grade tumours. High risk of pulmonary metastasis
Treat as per primary bone tumour guidelines
Fibrous dysplasia
Associated with McCune-Albright syndrome and Polyostic Fibrous Dysplasia
McCune-Albright = fibrous dysplasia + café-au-lai spots + endocrine abnormalities
Management of osteosarcoma
If left untreated will be fatal
Poor prognosis:
Aggressive local growth
Rapid haematological spread (15-20% present with pulmonary mets)
Poor response to chemotherapy agents
Multi agent chemo pre op 8-12 weeks
Repeat procedures to Stage the Tumour
Limb Salvage surgery (where possible) + adjuvant chemotherapy
Enchondromas
Benign lesions
Tend to occur in small bones (Hand, Foot)
Can occur anywhere in skeleton
Do not destroy bone
Xray – metaphyseal “popcorn”
Hot on a bone scan
Histology = “island of cartilage”
1% chance of malignant change
Chondroblastoma
Rare Epiphyseal tumour arising from chondral precursor cells.
Location: distal femur (most common), proximal humerus
Oval lytic lesion, sclerotic rim and soft tissue extension
Patient: Male - 10-20yrs
Similar to GCT (Giant Cell Tumour)
Chondrosarcoma
Histology important:
Grade I rarely metastasise (low grade)
Grades: II, III, and dedifferentiated (worst prognosis)
Dedifferentiated have 75% risk of mets and 10% survival
Chondrosarcomas are most commonly found in the pelvis
Mainstay of treatment = Surgery + adjuvant chemotherapy
Fibrous dysplasia
developmental abnormality of bone - Failure to produce normal lamellar bone, mutation of GS alpha protein
Can occur in any bone; Proximal Femur is the most common
Progressive in Children, Non-progressive in Adults
Can worsen during Pregancy (hormone receptors)
Can also be painful due to increased bone turnover or fracture
Increased risk of malignancy if Polyostotic
What do X rays show in fibrous dysplasia
Ground glass lesion with scleritic margin
Always include fibrous dysplasia on a benign looking bone lesion
Histology: “chinese alphabet”
Treatment for fibrous dysplasia
Medical = Biphosphonates
Surgical = Curettage and cortical autograft.
Non-ossifying fibroma
Variants of normal growth. Benign only.
Become more diaphyseal as child grows
Approx 55% around the knee; 80% LL
Radiographic features:
Eccentric[to one side of the bone]
Metaphyseal
Sclerotic rim
Unicameral bone cysts
Metaphyseal
Purely lytic
Expand the bone in a symmetric fashion
Often border the growth plate
May have trabeculations in them once they have fractured
Aneurysmal Bone Cyst (ABC)
Always biopsy if large or any doubt
Usually < 20yrs
Metaphyseal and eccentric
Xray: Eccentric, lytic, expansile lesion
Look for fluid levels on MRI
Treatment: simple curettage= 86% success
Giant cell tumours (GCT)
Locally destructive neoplasm with poorly defined cells
20-40yrs; F > M; Rare in Children
Benign but <2% metastasise to Lungs
Lesions: 50% in the knee; 30% Vertebrae and Sacrum
Always get biopsy - histology multinucleated cells
Xrays – destructive lesion, no sclerotic rim
Treatment: Curettage, washout, dental burr, +/- bone cement. 90% success rate
New treatment= Biphosphonates
Ewings Sarcoma
Small round cell tumour
Arises from neural crest cells
Children and young adults (rare if >30yrs)
Caucasians > Afro-carribean (9:1)
Clasically a diaphyseal lesion: femur, pelvis, tibia, humerus
Destructive lytic lesion
Balanced translocation
Investigation and treatment for Ewings
Bone Marrow Biopsy
monotonous blue cell tumour
indistinct cell borders
no matrix production by the tumour cells.
Typically chemo/radio-sensitive
Treatment:
chemotherapy, radiotherapy and surgical excision/reconstruction
Prognosis:
Poor if large tumour / pelvic / mets at Dx
70% survival overall; 30% if mets present
Adamantinoma
Rare tumour of long bones [tibia]
Young adults
PC: pain
X-ray: rediolucent zones interlaced with sclerosis and some cortical destruction.
Histology: epithelial cells in fibrous stroma (biphasic)
A low grade malignant lesion
But can metastasize to the lungs
Treatment: wide surgical excision plus reconstruction
Multiple myeloma
Malignant plasma cell disorder
Age: 50-80 years
PC: bone pain, pathological fracture, fatigue (anaemia)
Hypercalacemia
Renal failure secondary to amyloid
X-rays: punched out lytic lesions (pepper pot skull)
Bloods: serum electropheresis-monoclonal band
Urine: Bence-Jones proteins
Investigation and treatment for multiple myeloma
Histology: plasma cells, perinuclear halo
Treatment: surgical stabilisation and radiotherapy
Poor prognosis with aggressive variants
Lymphoma
Lymphoma of bone is uncommon
Can be an isolated lesion or a metastatic focus
All age groups
PC: pain +/- soft tissue masses
Common locations: distal femur, proximal tibia, pelvis, shoulder girdle
X-rays: bone destruction +/- reactive bone formation, thickened cortex
Histology: Marrow replacement with lymphoid cells
Treatment: chemo and radiotherapy. Surgery only used to stabilise fractures
Most common tumours of bony metastasis
Breast (Sclerotic/Mixed)
Lung (Lytic / Mixed)
Prostate (Sclerotic/Mixed)
Kidney (Lytic)
Thyroid (Lytic)
How does bony metastasis occur
Bone resorption via activation of Osteoclasts by tumour cells
PTHrP, RANK-L, IL-1, IL-6, TNF
RANK-L binds to RANK receptor on osteoclast
Mirel’s scoring system
scoring system for diagnosing impending pathological fractures.
4 parameters (3 points for each parameter- max score 12)
Site of lesion
Pain
Nature of lesion
Width of Cortical destruction
score of 9 has a 33% chance of fracture
Thus think prophylactic stabilisation if score of 8 or above.
Soft Tissue Sarcoma (STS)
Malignant tumour of connective tissue
Mutiple types:
Fibrosarcoma = Fibrous Tissue
Leiomyosarcoma = Smooth muscle
Rhabdomyosarcoma = Skeletal muscle
Liposarcoma = Fatty tissue
Synovial Sarcoma
What masses are considered malignant in Soft tissue sarcomas
Size >5cm
Deep to the Fascia
Enlarging in size
Painful
Management of soft tissue sarcomas
Chemo/Radiotherapy + Surgery
Higher % necrosis after neo-adjuvant radiotherapy = better prognosis
4 different surgical margins in oncological surgery
Intralesional: The plane of surgery goes through the tumour.
Marginal: The plane of surgery goes through the reactive zone of the lesion
Wide: The plane of dissection goes through normal tissue.
Radical: The entire anatomic compartment of the lesion is removed.
Local complications of surgery
Haematoma
Loss of function (NV injury)
Infection – Superficial / Deep (Silver coating of implants reduces risk)
Local Recurrence (especially if intra-lesional margin)
Systemic complications of surgery
Risks to general health
Distant Metastasis
Death
Multiple Hereditory Exotosis (Diaphyseal Achalasia)
Characteristic widening of the metaphysis
Large sessile osteochondromas arise from the metaphysis
Autosomal dominant.
The putative tumour suppressive gene mutation is EXT1, EXT2.
Low-grade chondrosarcoma occurs in this condition in approximately 10%.
Olliers Disease
Multiple enchondromatosis
Unilateral lesions
Dysplastic appearance of bone
30% risk of sarcomatous change
Maffuci Syndrome
Multiple enchondromas in association with angiomas
100% chance of malignant change
Association with other tumours: GI tumour, astrocytoma
Chordoma
A low-grade malignancy that has a high rate of local recurrence, but a low risk of metastasis.
Clasically seen in sacrococcgeal area. Grows anteriorly
Early symptoms = pelvic pain
Late symptoms = constipation, sacral nerve dysfunction
Although the 10-year survival rate is only approximately 25%, the majority of patients die from local spread rather than from metastases.
Treatment: Wide surgical resection. Resistant to chemoradiotherapy
