Histopathology 2 - Bone tumours Flashcards
What is the preferred investigation for diagnosing bone tumours?
Core biopsy under radiological guidance
What is “shepherd’s crook deformity” a reference to?
Fibrous dysplasia involving the femoral head
Recall 4 tumour-like conditions of the bone that are not actually malignant
- Fibrous dysplasia
- Fibroma (can be ossifying/ non-ossifying)
- Reparative giant cell granuloma
- Simple bone cyst
How does osteochondroma mimic bone in appearance?
They have a cartilaginous surface overlying normal cortical + trabecular bone
In which bones is osteochondroma most likely to present?
Long bones
How will enchondroma appear on XR?
Which bones are affected?
“popcorn” pattern
usually affects the fingers/hands
Is a giant cell tumour of bone benign or malignant?
Borderline malignant
What is the typical age of presentation of osteochondroma?
20-40 years
What is the typical age of presentation of giant cell tumour of bone?
20-40 years
How do giant cell bone tumours appear under the microscope?
Osteoclasts on a background of ovoid cells
What are the 3 types of malignant bone tumour?
Osteosarcoma (bone-forming)
Chondrosarcoma (cartilage-forming)
Ewing’s sarcoma (undifferentiated mesenchymal)
Recall the typical age of presentation for each of the 3 types of malignant bone tumour
Osteosarcoma: <30 years
Chondrosarcoma: >40 years
Ewing’s sarcoma: <20 years
Recall the typical site affected for each of the 3 types of malignant bone tumour
Osteosarcoma: knee
Chondrosarcoma: pelvis/ proximal skeleton
Ewing’s sarcoma: long bones + pelvis
Recall the typical X ray appearance of each of the 3 types of malignant bone tumour
Osteosarcoma: Codman’s triangle
Chondrosarcoma: fluffy calcification
Ewing’s sarcoma: Onion-skinning of periosteum
What is a “Codman’s triangle”?
The triangular area of new subperiosteal bone that is created when a lesion, often a tumour, raises the periosteum away from the bone.
Which of the 3 types of malignant bone tumour has the best prognosis?
Chondrosarcoma
*the adult one**
What gene mutation is associated with Ewing’s sarcoma?
11:22 translocation
Which type of malignant bone tumour will stain for CD99 and MICC2?
Ewing’s sarcoma
Which patients are most at risk of developing Ewing’s tumour in soft tissue?
Immunocompromised patients
What are the 5 metabolic bone diseases
Osteoporosis
Osteomalacia/rickets
Hyperparathyoridism
Paget’s disease
Renal osteodystrophy
Compare the aetiology of the 5 metabolic bone diseases
DEXA score in osteoporosis
<2.5 SD: osteoporosis
1-2.5: osteopaenia
Osteoporisis vs osteomalacia: disease features
Osteoporisis: decreased bone mass
Osteomalacia: decreased bone mineralization
Disease features of paget’s disease
Lytic and sclerotic lesions
Phases:
a) lytic
b) mixed
c) osteosclerotic
**also causes deafness**
Types of fractures seen in osteoporosis
Neck of femur
Wrist - colle’s fractures
Vertebral fractures
Features of rickets/osteomalacia
Adults:
bone pain/tenderness, proximal muscle weakness
Children:
Rachitic rosary
Bowing of legs
Bone pain
frontal bossing
pigeon chest
delayed walking