Orthopaedic Oncology Flashcards
Benign
Hasn’t breached basement membrane and likely won’t
Malignant
Has breached basement membrane and can metastasize
Enneking’s Four Questions (when looking at an XR)
- Location - epiphyseal, metaphyseal, diaphyseal
- Tumour-bone interaction - scalloping, border morphology
- Bone-tumour interaction - sclerotic margin, narrow/wide zone of transition
- Periosteal reaction - onion skin, sunburst, Codman’s triangle
Principles of biopsy
- Should be done by surgeon capable of resection after discussion with bone tumour unit
- Longitudinal, extensile incisions
- Must get lesional tissue
- Meticulous haemostasis, TQ down before closure and drain out through wound
- Don’t breach compartments/NV structures
- Excise biopsy tract
What’s a sarcoma?
Neoplasm derived from mesenchymal cell lineage
Metastasises via haematogenous spread
Can be bone or soft tissue
Spindle cells within dense stroma
Bone forming benign lesions (3 answers)
Osteoma
Osteoid osteoma
Osteoblastoma
Bone forming malignant lesions (1 answer)
Osteosarcoma
What is osteosarcoma?
Malignant neoplasm of bone
Can be primary or secondary
Types of primary osteosarcoma (4 types)
1 intramedullary, 3 surface types
- High grade intramedullary OS
- Periosteal OS
- Paraosteal OS
- Telangiectatic OS
Causes of secondary osteosarcoma
Secondary to Paget’s disease
High grade intramedullary osteosarcoma
Most common type
Occurs mostly around the knee - distal femur/prox tibia but also prox humerus
Young adults & children mostly but second peak > 65 years old (secondary to Paget’s)
Mostly metaphyseal
More aggressive and rapidly growing
Long term survival 60-70%
Treatment with neoadjuvant chemotherapy, surgery and chemotherapy +/- radiation
Chemo kills the micrometastases present in 80-90% patients at presentation and sterilizes reactive zone around tumour
Parosteal osteosarcoma
Low grade osteosarcoma
Common on posterior aspect of distal femur
Low grade so chemo not required
Treatment with wide margin surgical resection
Long term survival 95%
Periosteal osteosarcoma
Surface form of OS
Commonly appears radiologically as a sunburst-type lesion on a saucerized cortical depression
Treatment is with chemo and wide surgical resection
Long term survival 85%
Telangiectatic osteosarcoma
Described as ‘bag of blood’
Radiographic features similar to ABC - fluid filled sacs on MRI
Should be handled by a bone tumour unit
Treatment is chemo and wide surgical resection
Cartilage forming benign lesions (3 types)
Enchondroma
Osteochondroma - pedunculated or sessile
Chondroblastoma
Cartilage forming malignant lesions (1 type)
Chondrosarcoma
Enchondroma
Benign cartilage tumour in the medulla (osteochondroma if on surface)
Caused by incomplete endochondral ossification where chondroblasts and fragments of epiphyseal cartilage escape from physis into metaphysis and continue proliferating
Appear radiographically as areas of stippled calcifications
Can be difficult to differentiate from low grade chondrosarcoma
Most need no treatment
Most common tumour of phalanges
Associated with Ollier’s disease and Maffucci Syndrome
Pelvic lesions more likely to undergo malignant change and found later
BACTIP classification - size of scalloping, MRI, refer onwards.
Osteochondroma
Most common benign bone tumour (20-50%)
Caused by abherrant cartilage (most likely from perichondral ring) becoming trapped within metaphysis
Can be sessile (broad-based) or pedunculated (narrow stalk)
Characteristic appearance has medulla and cortex continuous with rest of bone
Typically occur at site of tendon insertions and bone can be abnormally wide
Often painful secondary to local compressive effect/bursitis - hence surgical treatment sometimes
Cartilage cap overlying stalk/sessile is ~2-3mm thick at skeletal maturity (10-20mm in children). In adults, if cartilage cap is >20mm or thickens then increased risk of chondrosarcomatous change
Sessile more likely to undergo malignant transformation
Can be isolated or linked with Multiple Hereditary Exostoses (EXT1-3 gene defect)
Chondrosarcoma
Malignancy of cartilage cells
Most common in 30-60 year olds
Can be primary or secondary:
Primary - central or periphery
Secondary - enchondroma (Ollier’s/Maffucci) or osteochondroma (MHE)
Most common around knee - distal femur, proximal tibia but also pelvis, ribs and long bones
Chordoma
Notochordal lineage
Central cervical or sacral
Rarely in vertebral bodies
Treatment is surgery but very challenging
Incidence is 1 in 1 million
Investigation of bone tumours
History
Examination including NV status
Bloods - FBC for infection/haematological malignancy, blood film (for myeloma) UE, LFT, clotting, G&S, calcium, bone profile, LDH, tumour markers (PSA, CEA, Ca125)
Urine - Paget’s, Bence-Jones protein for myeloma
Whole bone radiograph
Staging CT for primary lesion
Whole bone MRI looking for skip lesions, soft tissue invasion and NV involvement + contrast to establish if central necrotic core or infection
Systemic imaging - PET, NM whole body bone scan or whole body MRI (which East Midlands Sarcoma Service use in children)
Referral to bone tumour unit.
Biopsy
Management of bone tumours
Biopsy
Staging
Grading
Neoadjuvant chemotherapy
Surgery
Chemotherapy
+/- pre-op radiotherapy for big tumours (in soft tissue sarcoma)
