Pathology of Bone, Joint and Soft Tissue Flashcards
What are the bone forming tumours?
- Osteoma
- Osteoid osteoma and osteoblastoma
- Osteosarcomas
What are the cartilage forming tumours?
- Osteochondroma
- Chondromas
- Chondrosarcoma
What are the bone and related tumours?
- Bone forming tumours
- Cartilage forming tumours
- Fibrous and osseous tumours
- Miscellaneous (Ewing sarcoma, giant cell tumour, aneurysmal bone cyst)
- Metastases
What is Paget’s disease?
Disorder of bone formation resulting in deformity, decreased structural strength, increased bone mass and subsequent effects on other symptoms
What are the 3 phases of Paget’s disease?
- Lytic
- Mixed
- Burnt out
Cause of Paget’s disease?
- Hereditery component (SQSTM1 gene in 40-50% familial causes)
- Osteoclast activation
- x7 more common in first degree relatives
Epidemiology paget’s disease?
- Middle age - elderly
- M>F
- Rare
What is leontiasis osier?
Lion like face (big part of triangle at top of face) occurs as part of Paget’s disease.
Clinical features of Paget’s disease?
- Leontiasis ossea
- Long bone bowing
- Radiological cortex thickening
- Chalkstick and vertebral compression fractures
- Secondary osteoarthritis
How is Paget’s disease treated?
Calcitonin and bisphosphonates for treatment
Macroscopic features of Paget’s disease?
Thickened, deformed vascular bone
Microscopic features of Paget’s disease?
Mozaic, haphazard, jigsaw patterns with variable osteoclastic/blastic activity depending on the stage. Increased marrow vascularity
Causes of AVN?
All related to ischaemia
- Steroids
- Trauma
- Infection
- Dysbarism (gas emboli)
- Pregnancy (amniotic fluid emboli)
- Collagen disease
- Sickle cell disease
- Tumours
- Pancreatitis (fat emboli)
How does AVN often present?
Pain: acutely when subchondral; may result in OA. Depends on site
Macroscopic features of AVN?
- Medullary cancellous bone with well demarcated lesion
- Cortex has collaterals
- Cartilage is usually viable
- Fracture can occur
Microscopic features of AVN?
- Lacunae devoid of osteocytes
- Necrotic fat cells
- Sometimes sloughing of articular cartilage
What is osteomyelitis?
Inflammation of bone related to an isolated focus of infection but may be associated with system sepsis
Focus of dead bone fragment in centre of osteomyelitis lesion?
Sequestrum
Most common site of septic arthritis?
Knee
What is an osteosarcoma?
A malignant mesenchyal tumour in which the tumour cells produce bone
What is the cause of osteosarcoma?
- Mutations in RB and p53
- Cell cycle and DNA repair abnormalities seem important
Where are osteosarcomas most common?
Sites of bone growth; knee commonest at metaphysis (25%)
Age of osteosarcoma onset?
Bimodal incidence:
-75%
Radiographic features of osteosarcoma?
-Destructive lytic and blastic infiltrating lesion with reactive raised periosteum (Codman’s triangle)
General pattern of sarcoma v carcinoma spread?
Carcinoma by lymphatics
Sarcoma by blood
Microscopic features of osteosarcoma?
- Pleomorphic cells (sometimes multinucleated) with abnormal mitoses
- producig bone
- Multi centric or solitary
- Primary or secondary (e.g. Paget)
- Histological e.g. osteoblastic, chondroblastic, fibroblastic
What is a sarcoma?
Malignant soft tissue tumour
What is a benign/malignant skeletal muscle tumour?
Rhabdomyoma / rhabdomyosarcoma
