BONE TUMOUR RADIOLOGY

BONE TUMOUR RADIOLOGY

By Dr. KM Liau

1. Clues by appearance of lesion

2. Clues by location of lesion

3. Clues by type of periosteal reaction

4. Clues by matrix of lesion

5. Clues by density of lesion

6. Clues by number of lesion

1. Clues By Appearance Of Lesion

Patterns of Bone Destruction

1. Geographic

2. Moth-eaten

3. Permeative

Geographic Bone Destruction

Destructive lesion with sharply defined border

Implies a less-aggressive, more slow-growing, benign process

Narrow transition zone

Examples:

1. Non-ossifying fibroma

2. Eosinophilic granuloma

NON OSSIFYING FIBROMA

30 to 40% children over two years have one or more lesions

Most common between 8-20 years of age

Usually occur in metaphysis of one (75%) or more (25%) of the tubular bones

Most lesions heal spontaneously by being replaced with normal bone

May undergo pathologic fracture

Do not undergo malignant transformation

NON OSSIFYING FIBROMA - X-ray characteristics:

* Geographic

* Lytic

* Multilobulated

* Metaphyseal

* Usually intramedullary

* Eccentric

* Well-marginated

* Sclerotic rim

* Endosteal scalloping

New The Most Important Thing

Non-ossifying fibroma of tibia

Eosinophilic Granuloma

Solitary, non-neoplastic proliferation of histiocytes.

Part of a spectrum of Langerhan's cell histiocytosis, formerly known as histiocytosis X.

Localized lesion in bone or lung and occurs most commonly in children aged 5 to 10.

EG is found in the diaphysis or metaphysis of long bones in the center of the medullary cavity.

The radiologic differential includes Ewing's sarcoma, osteosarcoma, metastases and osteomyelitis.

Eosinophilic granuloma of femur

Moth-eaten Appearance

Areas of destruction with ragged borders

Implies more rapid growth - High probability of malignancy

Example:

1. Myeloma

2. Metastases

3. Lymphoma

4. Ewing's sarcoma

Multiple myeloma

Multiple myeloma is a malignant tumor of plasma cells that causes widespread osteolytic bone damage.

The average patient age is over 50 years old and men are affected twice as often as women.

Characterized by irregular lytic defects of different sizes.

These lytic areas are often described as "punched out" and have no periosteal reaction.

Erosion begins intramedullarly and progresses through the cortex.

Multiple myeloma of humerus with pathological fracture

Permeative Lesion

Ill-defined lesion with multiple "worm-holes"

Spreads through marrow space

Wide transition zone

Implies an aggressive malignancy -Round-cell lesions

Examples:

1. Lymphoma

2. Leukemia

3. Ewing's Sarcoma

4. Myeloma

5. Neuroblastoma

6. Osteomyelitis

2. Clues By Location Of Lesion

1. In the transverse plane:

a) Central - Enchondroma

b) Eccentric -GCT, osteosarcoma, chondromyxoid fibroma

c) Cortical - Non-ossifying fibroma, osteoid osteoma

d) Parosteal - Parosteal osteosarcoma, osteochondroma

2. In the longitudinal plane:

a) Epiphyseal - GCT, chondroblastoma

b) Metaphyseal - Osteomyelitis, osteosarcoma

c) Diaphyseal - Round cell lesions, ABC, enchondroma

Osteoid osteoma

Osteoid Osteoma is a benign bone lesion with a nidus of less than 2 cm surrounded by a zone of reactive bone.

Osteoid osteoma has a distinct clinical picture of dull pain that is worse at night and disappears within 20 to 30 minutes of treatment with non-steroidal anti-inflammatory medication.

4 diagnostic features include

(1) a sharp round or oval lesion
(2) less than 2 cm in diameter,
(3) has a homogeneous dense center
(4) a 1-2 mm peripheral radiolucent zone.

Osteoid osteoma of transverse process of vertebra

Osteoid osteoma of fibula

Characteristic Location

Simple bone cyst - Proximal humerus

Chondroblastoma - Epiphyses

Giant Cell tumor - Epiphyses

Adamantinoma - Tibia

Chordoma -Sacrum

Osteoblastoma - Posterior element of spine

Parosteal osteosarcoma - Distal femur

Periosteal osteosarcoma - Tibia

Chondrosarcoma - Pelvis

SIMPLE BONE CYST

Solitary cystic lesion over the proximal humerus.

Multiple septations.

Thinned out cortex.

Sclerotic border with narrow zone of transition signifies a benign process.

Note: abscence of periosteal reaction differentiates it from aneurysmal bone cyst. (Find out more in my lens on lytic bone lesion).

Solitary bone cyst of femur

CHONDROBLASTOMA

Chondroblastomas are radiolucent lesions that typically occupy the epiphysis (or apophysis) of long bones.

They tend to be small (< 4 cm) with most exhibiting a sclerotic border.

A calcified matrix is seen on radiographs in one third of patients.

May mimic giant cell tumor when they extend into the metaphysis and lack sclerotic margins and calcification.

But unlike giant cell tumor, chondroblastomas present in a younger age group, usually before skeletal maturity.

Extension of tumour into soft tissues is rare with chondroblastoma.

Chondroblastoma of distal femur

GIANT CELL TUMOUR

X Ray finding:

Solitary expansile lytic lesion

Multiple septation (soap bubble appearance)

No reactive sclerosis

Metaphyseal region

Adjacent to epiphyseal line

Justa-articular if epiphyseal plate is fused

Giant Cell Tumour

Characteristic X Ray finding:

Solitary expansile lytic lesion

Multiple septation (soap bubble appearance)

No reactive sclerosis

Metaphyseal region

Adjacent to epiphyseal line

Justa-articular if epiphyseal plate is fused

Giant cell tumour of distal radius

ADAMANTINOMA - TIBIA

Adamantinoma is a locally aggressive osteolytic tumor that is found 90% of the time in the diaphysis of the tibia with the remaining lesions found in the fibula and long tubular bones.

Adamantinoma appears as an eccentric, well-circumscribed, and lytic lesion on plain x-ray.

The lesion usually has several lytic defects separated by sclerotic bone.

There is cortical thinning but little periosteal reaction.

3. Clues By Type Of Periosteal Reaction

Benign - None or Solid periosteal reaction

More aggressive or malignant

1. Lamellated or onion-skinning

2. Sunburst

3. Codman's triangle

(More explanation in my lens on Periosteal Reaction)

4. Clues By Matrix Of Lesion

1. Ossification (Osteoblastic process) - Well organized ossified mass with fluffy, cotton-like or cloud-like densities. Eg. Osteosarcoma.

2. Calcification (Cartilaginous process)- Unorganized calcified matrix which is comma-shaped, punctate, annular or popcorn-like. Eg. Enchondroma, Chondrosarcoma, Chondromyxoid fibroma.

OSTEOSARCOMA

Well organized mass signifying osteoblastic process.

Sunburst periosteal reaction and soft tissue mass signifies an aggressive and rapidly growing tumour.

Osteosarcoma of distal femur

CHONDROSARCOMA

Calcified matrix (unorganized) signifies cartilaginous tumour.

The wide zone of transition and cortical break without periosteal reaction signifies a rapidly growing and aggressive type of tumour.

Chondrosarcoma of left ilium. Note the extensive calcification.

5. Clues By Density Of Lesion

1. Sclerotic Cortical lesions
- Osteoid osteoma
- Brodie's abscess
- Stress fracture

2. Lytic lesions in children
- Eosinophilic granuloma
- Neuroblastoma
- Leukemia

3. Lytic lesions in adult
- Metastatic lesions (Lung, Kidney, Thyroid)
- Multiple myeloma
- Primary bone tumor

4. Blastic lesion in children
- Medulloblastoma
- Lymphoma

5. Blastic lesion in adult
- Metastatic disease (Breast, Prostate)
- Lymphoma
- Paget's disease

6. Clues by number of lesion

Multiple lesion: More often benign

Malignancies with multiple lesions
- Metastatic disease
- Multiple myeloma
- Lymphoma

Bone Tumour Link List

Bone Tumour

Very informative source about bone tumour

Sarcoma

Very informative source for Sarcoma

Ewing Sarcoma AAOS

Learn more about Ewing Sarcoma at AAOS

Ewing Sarcoma

Tutorial on Ewing Sarcoma

Unicameral bone cyst

Unicameral (simple) bone cyst information

Giant Cell Tumour

Giant cell tumour information