Cortext - Pathology Flashcards
Describe an osteochondroma?
Where do they commonly occur?
Risk of malignant transformation?
Bony outgrowth on external surface of bone covered in a cartilaginous cap
Around epiphysis of long bones, most common around the knee
1% risk of malignant transformation - any lesion growing in size or causing pain may require excisional biopsy
(multiple osteochondromas assoc w genetic conditions)
Describe an enchondroma?
What can happen to it to change its appearance?
Where do they occur?
Management?
Intramedullary, metaphyseal cartilaginous tumour
It can undergo mineralisation with a patchy sclerotic appearance
Small, tubular bones of hands and feet
Scraped out of bone if causing bother. Usually an incidental finding or cause of pathological fracture
Describe a simple (unicameral) bone cyst?
Cause?
Where are they found?
Management?
Solitary unicystic fluid-filled neoplasm
Probably a growth defect from physis (therefore metaphyseal in long bones)
Long bones - proximal humerus/femur, but also in talus/calcaneus
Usually incidental finding - if cause of pathological fracture then curettage and bone grafting
Describe an aneurysmal bone cyst? Cause? Where do they occur? Consequence? Management?
Cyst with many chambers, filled with blood or serum - the chambers can be seen on XR
Small AVM
Metaphysis of long bones, flat bones (ribs, skull), vertebral bodies
Can be locally aggressive causing cortical expansion and destruction, usually painful
Risk of pathological fracture - treat with curettage and grafting or bone cement
Describe a giant cell tumour? Where do they occur? Histology? XR appearance? Management? Malignant transformation?
Locally aggressive metaphyseal tumour which can extend to subchondral bone and epiphysis
Knee and distal radius but can affect other ling bones, pelvis or spine
Multi-nucleate giant cells, characterised by translocation between chromosome 1 and 2
Soap bubble appearance
Can cause pathological fractures, treat with phenol, bone cement and liquid nitrogen.
5% met risk to lungs
Describe fibrous dysplasia? Where does it affect? Cause? What bone problems can it lead to? What is seen on bone scans? Management?
Lesions of fibrous tissue and immature bone in adolescence due to a genetic mutation
Any bone, but most commonly head & neck
Abnormal G-protein signalling
Angular deformities, e.g. Shephard’s crook deformity of proximal femur - caused by defective bone mineralisation
Increased uptake during development, but lesions become inactive
Bisphosphonates reduce pain
ORIF for fractures
Describe an osteoid osteoma? Where do they occur? Clinical features? Ix? Management?
Small nidus of immature bone surrounded by intense sclerotic halo
Proximal femur, diaphysis of long bones and vertebrae - usually in adolescence
Intense, constant pain worse at night
(mediated by PG’s, NSAIDs relieve pain)
Can be seen on XR but bone scan/CT confirmatory
May resolve spontaneously, may need CT-guided radiofrequency ablation or en bloc excision
What is a Brodie’s abscess?
Subacute osteomyelitis - can present as lytic lesion of bone
What is a Browns tumour?
Hyperparathyroidism - can preset as lytic lesion of bone
When are bone tumours more common?
When are primary bone tumours more common?
In older age, but metastatic from e.g. prostate, breast, lung - or myeloma
Primary bone tumours are more common in younger patients
How can primary bone tumours sometimes show up early on?
ill-defined bony swelling on XR - this mandates further Ix
Unexplained MSK pain (commonly misdiagnosed as growth pains)
Systemic symptoms may then appear
How can malignant primary bone tumours show up XR?
Aggressive and destructive signs
- Cortical destruction
- Periosteal reaction (raised periosteum producing bone)
- New bone formation (sclerosis as well as lysis from destruction)
- Extension into surrounding soft tissues
What is the most common primary bone malignancy? Gene association? Age? Location? Mets? Management?
Osteosarcoma - bone-producing tumour
Mutation in tumour suppressor retinoblastoma
gene
Bones around knee (60%),, proximal femur, proximal humerus, pelvis
Adolescence/early adulthood
Haematological - most commonly to lung
Chemo
What is a chondrosarcoma? Age? Growth/mets? Location? Management?
Cartilage-producing primary bone tumour - less common and less aggressive than osteosarcoma
Older (mean 45 yo)
Can grow to be large, slow to metastasise
Pelvis/prox femur
Not radio/chemo-sensitive
What is a Ewing's Sarcoma? Age? Where? What is seen radiologically? Gene? How does it present?
More commonly occurring bone tumour of uncertain cell origin, similar to neuroectodermal tumours
(small round blue cell tumours)
Young
Long bones
Onion-skin pattern
t11;22 EWS gene
Fever, raised inflam markers, warm swelling - may be mis-diagnosed as osteomyelitis
Radio&chemo-sensitive
