Reactive lesions Flashcards
Uincameral Bone cysts Aneusrysmal Bone cysts
1
Q
What are unicameral bone cysts?
A
- Aka simple bone cysts
- a non neoplastic, serous fluid bone lesion though to result from temporary failure of medullary bone formation near the physis
- pts <20 yrs
- location
- proximal humerus- usually
- prox fem, distal tibia, ilium, calcaneus, MC, distal radius
- metaphysis adj to physis
- progresses towards diaphysis w bone growth
2
Q
What is the prognosis of unicameral bone cysts?
A
- As pt approaches skeletal maturity bone cyst will
- decrease in size and may heal after growth complete
- fx healing doesn’t -> cyst resolution
- Follow up in active phase due to recurrence and risk of fx or growth arrest
3
Q
What are the classification of unicameral bone cysts?
A
-
Active
- if cyst is adjacent to physis
-
Latent
- if normal bone separates cyst from physis- see pic
4
Q
What are the symptoms of unicameral bone cysts?
A
- Aysymptomatic unless fx
- Pain from path fx -50%
5
Q
What is seen on radiographs with unicameral bone cysts?
A
-
Central, lytic, well demarcated metaphyseal lesion
- 2-3 % cross physis
- Cystic expansion w symmetrical thinning of cortices
- Fallen leaf sign - path fx with fallen cortical fragment in base of empty cyst
- MRI- v dark on T1, very bright T2
- Bone scan variable, usually warm
6
Q
What is seen on histology of unicameral bone cysts?
A
- Cyst with Thin fibrous lining containing fibrous tissue, giant cells and haemosiderin pigment
7
Q
What is the ddx if a unicameral bone cysts?
A
-
Aneurysmal bone cyst
- more expansile than UBC
- UBC is usually not wider than physis
- Telangiectatic osteosarcoma
8
Q
What is the tx of unicameral bone cysts?
A
Non operative
-
immobilzation alone
- prox humeral path fx
- 15% lesions will fill in w native bone after acute fx
-
Aspiration/methylprednisolone acetate injection
- active cysts in prox humerus
- usually several injections esp in v young kids
Operative
-
Currettage and bone grafting+/- internal fixation based on tumour location
- latent cysts as risk of fx/osteonecrosis
- prox femoral lesions- path fx-> high rate refx and malunion when tx nonop.
- avoid in active lesions as communication w physis may-> growth arrst
9
Q
What is an aneurysmal bone cyst?
A
- A Benign and non neoplastic reactive bone lesion filled with multiple blood-filled cavities
- can be locally destructive to normal bone
- may extend into softt tissue
- 75% pts are <20 yrs
- location
- 25% spine
- 20% long bones
- usually Metaphysis
- post elements of pelvis
-
types
-
primary ABC
- now known neoplasm due to upregualtion of ubiquitin-specific protease USP6 gene on 17p13
-
Secondary ABC
- not neoplastic - no translocation
-
primary ABC
10
Q
Any associated conditions of aneurysmal bone cyst?
what is the prognosis of aneurysmal bone cyst?
A
- Assoc with Other tumours 30% time
- Giant cell tumour
- chondroblastoma
- fibrous dysplasia
- chondromyxoid fibroma
- NOF
Prognosis
- Good
11
Q
Describe the symptoms of aneurysmal bone cyst?
A
- Pain and swelling
- Path fx
- neurological deficit possible w spinal lesions
12
Q
What is seen on imaging of aneurysmal bone cyst
A
- Expansile, eccentric, lytic lesion with Bony septae= Bubby appearance
- Usually in metaphyseal bone
- thin rim perosteal new bone around lesion
- no matrix mineralisation
- MRI
- multiple fluid lines - see pic
- lesion can expand into soft tissue
13
Q
What is the histology of aneurysmal bone cyst?
A
- Cavernous space
- blood filled spaced without endothetial lining
- cavity lining
- numerous benign giant cells
- spindle cells
14
Q
What is the tx for aneurysmal bone cyst?
A
Non operative
-
non operative fx management
- ABC w acute fx
- indicated until fx healed. once healed, tx as an ABC withouf fx, unless fx-> spontanous healing of ABC
Operative
-
Aggressive curettage and bone grafting
- symptomatic ABC without fx
- some use adjuvant tx ( phenol)
- local reoccurance up to 25%, more common in children w open physes
