ABC

Definition

 

Expansile pseudotumor of reactive hemorrhagic tissue arising in bone

- characterised by blood filled spaces separated by fibrous tissue

 

Types

 

Primary 50%

- arise de novo 

 

Secondary 50%

- in association with other tumours 

- probably secondary to haemorrhage into 1° tumour

- GCT / chondroblastoma / osteoblastoma / osteosarcoma

- often only small component

- should treat as underlying 1° tumour

 

Site

 

Metaphysis of long bones

- proximal humerus

- femur

- tibia

 

Posterior elements of vertebra

 

Epidemiology

 

Teenagers

- 80% occur in 10-20 year range

 

F>M

 

NHx

 

Pathological fracture rare

May resolve with fracture or skeletal maturity

 

X-ray

 

Multi-loculated lesion

- eccentric

- expansile

- cortical thinning

 

ABC Proximal HumerusABC Distal Femur

 

Bone Scan

 

Usually increased uptake

- centre may have decreased uptake

 

Exclude polyostotic disease

 

MRI 

 

Haemosiderin content

- low to intermediate signal on T1 and T2

 

ABC MRI Distal Femur

 

Fluid - Fluid levels 

- due to sedimentation of RBC's & serum within the cavities

- patient must remain motionless for 10 minutes prior to the scan being performed

- allows time for sedimentation

 

 ABC Fluid Fluid Levels MRI

 

DDx

 

Fibrous dysplasia

GCT

ABC

Infection

Unicameral Bone Cyst

Osteosarcoma

 

Pathology

 

Gross

 

Blood filled spaces with fibrous septa

 

Histology

 

Cells

- haemosiderin-laden macrophages

- multinucleated giant cells

 

Septa

- fibrous stroma

- small amounts of osteoid

 

Management

 

Non operative

 

Can observe majority

- need to avoid contact sports

 

Operative

 

Indications

 

Biopsy / diagnose

Potential instability - proximal femur / spine

Pain

Recurrent fracture / debilitating

 

Options

 

Currettage and bone graft

Allograft / Joint Replacement

Embolisation

Sclerotherapy

 

Currettage and bone grafting

 

ABC Currettage and Bone GraftingABC Bone Grafting

 

Concept

 

Principles of biopsy approach

- confirm diagnosis on frozen section

- proceed to treatment

 

Indication

 

Must be able to preserve articular surface

 

Technique

 

Full and careful curettage

- intra-lesional treatment

- need to burr away all of lesion

- must take care as bone very thin

- areas of fracture not uncommon

- must beware growth plates in skeletally immature

- supplement with bone graft / bone marrow aspirate / PMMA

 

Resection and Allograft / TJR

 

Indications

 

Articular cartilage not salvageable

 

ABC Grade 3ABC Grade 3 Bulk Structural Allograft

 

Selective Arterial Embolisation

 

Indications

- preoperative in spine lesions

 

Results

 

Rossi et al Skeletal Radiol 2010

- 55 cases both spine and appedicular with N butyl cryanoacrylate

- successful in 94% cases

- a second (25%) and third (14%) embolisation required

- 2 cases of skin necrosis and one transient paresis

 

Sclerotherapy

 

Results

 

Rastogi et al JBJS Br 2006

- percutaneous sclerotherapy with polidocanol in 72 patients under II guidance

- all had histological diagnosis prior to treatment

- 84.5% clinical response

- required between 1 and 5 treatments (average 3)

- 2 recurrences successfully treated with repeat sclerotherapy

 

Varshney et al Clin Orthop Relat Research 2010

- RCT of sclerotherapy v intralesional resection of 94 ABCs

- 3 year follow up

- 93% healing in sclerotherapy group with minimal complications

- 84% healing in operative group with 3 deep and 5 superficial infections and 2 growth disturbances

 

Spine

 

Papagelopoulos et al Spine 1998

- 52 cases in the spine

- treated with extralesional and intralesional excision with bone grafting

- 10% recurrence at 10 years, all presenting within 6 months post surgery

- 4 patients had postoperative radiotherapy

- 1 died of radiation related osteosarcoma, 1 of intraoperative bleeding

- now recommend preoperative embolisation