Benign bone lesions Flashcards
What is osteochondroma
Benign bony lesion that arises from perichondral ring
What is the perichondral ring
Circumferential fibrous layer that secures the epiphysis and metaphysis together
Where is osteochondroma found
At the end of the bone near growth plate
Osteochondroma is commonly seen in which age group
Adolescents and young adults 10-20 years old
Osteochondroma can be solitary or multiple. Multiple osteochondroma can be due to
autosomal dominant disorder: Multiple hereditary Exostosis
Describe the structure of osteochondroma
Bony outgrowth near the end of the bone with a cartilaginous cap
Clinical presentation of osteochondroma
Painless
Hard lump
May have pain / numbness during activities
Osteochondroma commonly occur at
Distal femur
Proximal tibia
Investigations for osteochondroma
Xray or MRI
Management for osteochondroma
Close observation
may require removal if it grows or causes pain
Risk of osteochondroma developing into malignancy is
Small <1%
but higher in multiple hereditary exostosis due to more lesions
What is enchondroma
Intramedullary and metaphyseal cartilaginous tumour
Cause of enchondroma
Failure of endochondral ossification
What is endochondral ossification
Process of bone formation where cartilage is gradually replaced by bone
Which bones are not formed by endochondral ossification
Skull
Mandible
Clavicles
Enchondroma usually presents in which age group
20-50
Where does enchondroma occur
Intramedullary, at metaphysis
Which bones are commonly affected by enchondroma
Femur
Humerus
Tibia
Small bones of hands and feet
Enchondroma can lead to
Pathological fractures because they can weaken the bone
but usually asymptomatic
Investigations for enchondroma
Xray
Presentation of enchondroma on Xray
Lucent
Patchy sclerotic appearance
Management of enchondroma
curettage then fill with bone graft if there is risk of pathological fracture / fracture already occurred
What is a bone cyst
Benign fluid filled cyst in bone
Where is bone cyst usually located at
Metaphysis
Which bones are usually affected by bone cysts
Proximal humerus
Femur
Talus
calcaneus
What can bone cysts lead to
Pathological fracture due to weakening of the bone
But usually asymptomatic
Investigations for bone cysts
Xray
Management of bone cysts
Curettage then fill with bone graft
What is aneurysmal bone cyst
Lesion made of many chambers filled with blood or serum in bone
Cause of aneurysmal bone cyst
Small arteriovenous malformation
Where does aneurysmal bone cyst usually occur
metaphyses
What type of bones do aneurysmal bone cyst affect
Long bones
Flat bones - skull / clavicle/ scapula / mandible ..etc
Vertebral bodies
Symptoms of aneurysmal bone cyst
Painful mass
Swelling
pathological fracture
Investigations for aneurysmal bone cyst
Xray
Management of aneurysmal bone cyst
Curettage then bone graft
What is giant cell tumour of bone
Benign lesion arising from the giant cells of the bone marrow
Where does giant cell tumour of bone usually occur
Metaphyseal region
Involves epiphysis
Can extend to adjacent subchondral bone in joint
What is subchondral bone
The bone tissue lying beneath cartilage in a joint
Clinical presentation of giant cell tumour of the bone
Painful mass
Swelling
Pathological fracture
Which bones are commonly affected by giant cell tumour of the bone
Knee
Distal radius
Pelvis
Spine
other long bones
Xray presentation of giant cell tumour of the bone
Soap bubble appearance
Histology of giant cell tumour of the bone will show
Multi-nucleated giant cells
Management of giant cell tumour of the bone
Phenol / Bone cement / Liquid nitrogen
Joint replacement if damage to cortical layer of bone
Giant cell tumour of the bone can metastasise to
Lungs as benign pulmonary giant cell tumour
What is fibrous dysplasia
Benign, developmental disorder of bone that causes normal skeletal tissue to be replaced by fibrous tissue
Cause of fibrous dysplasia
Genetic mutation
Fibrous dysplasia usually occurs in which age group
Adolescents
Clinical presentation of fibrous dysplasia
Deformities
Bone pain
Pathological fractures
What happens to the bone structure in fibrous dysplasia
Affected bone is wider with thinner cortical layer
Investigations for fibrous dysplasia
Bone scan
Xray
Bone scan result for fibrous dysplasia
Increase in uptake of radioactive substances during development of the lesion
then becomes inactive
Xray presentation of fibrous dysplasia
Shepherd’s crook
Management of fibrous dysplasia
Bisphosphonates
Internal fixation
Cortical bone grafts
What is osteoid osteoma
Benign bone-forming tumors that typically occur in children
Osteoid osteoma usually affects which bones
Proximal femur
Diaphysis of long bones
Diaphysis of vertebrae
Clinical presentation of osteoid osteoma
Constant severe pain
Pain worse at night
Pain relieved by NSAID
Investigations for osteoid osteoma
Bone scan - increased uptake
CT
Presentation of osteoid osteoma on CT
Lucent nidus surrounded by sclerotic bone
What is nidus
Center of an osteoid osteoma, consists of growing tumour cells, blood vessels and cells that form bone
Management of osteoid osteoma
May resolve spontaneously
If not -> CT guided radio frequency ablation
What are lipomas
Benign soft tissue lesion due to neoplastic proliferation of fat
Characteristics of soft tissue neoplasm like lipomas
Smaller
Fluctuates in size
Well defined lesions
Fluid filled lesions
No overlying skin changes
Fatty lesions
Risk factors of bone cancer
Young
Previous radiotherapy
Paget’s / Multiple enchondromas / Fibrous dysplasia
Li Fraumeni syndrome
Familial retinoblastoma
Malignant bone tumours are often found at early / late stages
Late
What is Li Fraumeni syndrome
Inherited disorder predisposing people to malignancies due to mutation in p53
Li Fraumeni syndrome is inherited in which pattern
Autosomal dominant
Types of malignant bone tumours
Multiple myeloma
Osteosarcoma
Chondrosarcoma
Ewing’s sarcoma
Fibrosarcoma
What is multiple myeloma
Malignancy from plasma cells in the bone marrow
4 characteristics of Multiple myeloma
Hypercalcaemia
Anaemia
Renal impairment
Bone pain
Multiple myeloma usually affects which age group
Elderly
Most common type of sarcoma
Osteosarcoma
What is osteosarcoma
Malignant tumour that produces bone
How does osteosarcoma usually spread
Haematogenous
Osteosarcoma that occurs in elderly is associated with
Paget’s disease
Which bones are commonly affected by osteosarcoma
Distal femur
Proximal tibia
Proximal humerus
Pelvis
What is chondrosarcoma
Malignany of chondrocytes causing production of cartilage
How often does chondrosarcoma arise from benign lesions such as enchondroma and osteochondroma
Rare, most arise de novo
Which bones are often affected by chondrosarcoma
Pelvis
Proximal femur
How aggressive is chondrosarcoma
Less aggressive than osteosarcoma
Slow to metastasise
Chondrosarcoma tends ot affect which age group
45 years old; older age group
What is fibrosarcoma
Fibrous malignant tumours
Fibrosarcoma tend to affect which bones
Abnormal bones such as bone infarcts / post radiation bones
Which age group is usually affected by fibrosarcoma
Young adults / adolescents
What is Ewing’s sarcoma
Tumour of the endothelial cells of the bone marrow
2nd most common bone tumour in children is
Ewing’s sarcoma
Ewing’s sarcoma tend to affect which age group
10-20
Presentation of Ewing’s sarcoma
Hot, swollen, tender joint
which bones are often affected by Ewing’s sarcoma
Distal femur
Proximal tibia
Investigations for bony tumours
Xray
Biopsy
Staging using bone scan, CT, MRI
What would the xray results be for malignant bone tumours
Aggressive
Cortical layer damaged
Sclerosis
Loss of bone - lysis
Management of malignant bone tumours
Surgery
Adjuvant chemotherapy /radiotherapy
Neo-adjuvant chemotherapy
Which type of malignant bone lesion does not respond to chemotherapy
Chondrosarcoma
What are the cancers that commonly metastasise to the bone
Breast
Prostate
Lungs
Renal cell carcinoma
Thyroid cancer
Prostate cancer often gives which type of metastases
Sclerotic metastases
Lung cancer often gives which type of metastases
Lytic metastases
Renal cell carcinoma often gives which type of metastases
Large, very vascular lytic metastases
These can bleed a lot during biopsy or surgery
