1.Giant cell tumour2.Aneurysmal bone cyst

Giant cell tumour

• Also known as Osteoclastoma

• Common benign tumour

• Locally aggressive

• recurrence

Epidemiology

• 18-23% of benign bone neoplasm

• 20-50 years of age(80%)

• Mild female predilection especially when located in spine

• Malignant transformation(M:F=3:1)

Clinical presentation

• Pain

• Swelling

• Pathological fracture

• Compression of adjacent structures

Pathology

• Richly vascular tissue

• Plump spindle cells

• Numerous giant cells

• Neither bone nor cartilage forming

Location

• Solitary lesion

Around knee(50-65%)

Distal radius(10-12%)

Sacrum (4-9%)

• Multifocal lesions(0.5%)

Hands

staging:

- stage I:

• - benign latent giant cell tumors;

• - no local aggressive activity;

- stage II:

• - benign active GCT;

• - imaging studies demonstrate alteration of the cortical bone structure;

- stage III:

• - locally aggressive tumors;

• - imaging studies demonstrate a lytic lesion surrounding medullary and cortical bone;

- there may be indication of tumor penetration through the cortex into the soft tissues

Radiographic features

1. Closed growth plate

2. Abuts articular surface(within 1cm of articular surface)

3. Well defined with non sclerotic margins

4. eccentric

Plain film and CT

• Zone of transition

• No surrounding sclerosis

• Expansile

• Periosteal reaction

• Soft tissue mass

• Pathological fracture

• No matrix calcification/mineralization

MRI

T1

• Low to intermediate solid component

• Low signal periphery

T2

• Intermediate to high signal

• High signal in adjacent bone marrow represent inflammatory edema

a giant cell tumor presenting as an eccentriclytic lesion in the medial epi- and metaphysis of the distal femur. There is a small transitional zone resulting in well-defined borders.

Sagittal T1-weighted TSE images before and after Gd.

The tumor extends to the subchondral bone plate with endosteal cortical involvement.

There is inhomogeneous enhancement.

Scintigraphy

• doughnut sign, contiguous bone activity

Angiography

Differential diagnosis• Aneurysmal bone cyst

• Giant cell rich osteosarcoma

• Chondroblastoma

• Brown tumour of hyperparathyroidism

• Monoostotic fibrous dysplasia

• Large subarticular geode

• There is a well-defined lytic lesion located posteriorly in the proximal epiphysis of the tibia.

• there is some reactive sclerosis surrounding the lesion. There is no matrix formation.

• On the coronal T2-weighted image with fat suppression the lesion has a high SI and subtle internal ridges. There is edema of the entire epiphysis. On a sagittal T1-weighted image there is a discrete sclerotic margin.

Treatment and prognosis

• Curettage and packing

• Chemotherapy

• Radiotherapy

• Monoclonal antibodies

• Local recurrence

2.Aneurysmal bone cyst• Benign

• Blood filled

• Expansile tumour like bone lesions

• Uncertain etiology

Epidemiology

• Children and adolescent

• Less than 20 years of age

Clinical presentation

• Pain

• Palpable lump

• Pathological fracture

• Restricted movements

Pathology

• Primary

• Secondary

Chondroblastoma

Fibrous dysplasia

Giant cell tumour

osteosarcoma

Location

• Long bones(50-60%)

o Lower limb(40%)Tibia and fibula(24%)

Femur(13%)

o Upper limb(20%)

• Spine(20-30%)

• sacrum

Radiographic features

Plain film and CT

• Sharply defined

• Expansile

• Osteolytic lesion

• Thin sclerotic margins

• Fluid levels

• Bone scan (doughnut sign)

• Angiography

MRI

• Fluid-fluid levels

• Solid component

• Surrounding rim of low T1 and T2

• Focal areas of high T1 and T2

• The plain radiograph shows a layered periosteal reaction and Codman triangle in direct relationship to an expansile lytic lesion with a thin peripheral bone shell.

• CT also reveals the subperiostealorigin of the lesion with secondary involvement of the cortical bone.

• Axial T2-weighted image with fatsat and contrast enhanced T1-weighted image with fat sat show multiple fluid-fluid levels with rim enhancement of the cavities filled with blood.

• This is typical for an aneurysmal bone cyst.

• On the left images of an aneurysmal or expansilewell-defined osteolyticbone lesion in the fibula.

• The T2-weighted MR-image shows the fluid content and on the T1-weighted image there is a subtle fluid-fluid level.

DDs

• Giant cell tumour

• Osteoblastoma

• Osteoid osteoma

1 x 0.5 cm, nidus, oval lucent focus within surrounding sclerosis is seen involving the region of neural arch of L5 vertebra body at its inferioposterior aspect showing some eccentric bony expansion. These findings are typical of Osteoid Osteoma

Treatment and prognosis

• Curettage

• Radiotherapy

• Transcatheter embolisation

• Percutaneous fibrosing agent

Comparison

Giant cell tumour Aneurysmal bone cyst

20-50 years of age <20 years

Around knee and wrist Wide spread distribution

Subarticular Rarely extend to articular surface

eccentric Central

Non sclerotic margins Thin marginal sclerosis

Ill defined margins Well defined margins

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