Pathology

Question 1

Osteochondroma

What is it, where is it found, management

Answer 1

BENIGN
Most common benign bone tumour

Epiphysis of long bones
Most common around the knee

Very small risk of malignant transformation

*Excisional biopsy

Question 2

Enchondroma

What is it, where is it found, management

Answer 2

BENIGN
Metaphyseal cartilaginous tumour

Asymptomatic
Pathological fractures

Short tubular bones - hands and feet

*Scraped out

Question 3

Simple bone cyst

What is it, where are they found, management

Answer 3

BENIGN
Fluid filled

Asymptomatic
Pathological fractures

Long bones - proximal humerus and femur, also talus and calcaneus

*Curettage and bone grafting

Question 4

Aneurysmal bone cyst

What is it, where is it found, management

Answer 4

BENIGN
Lucent multi-loculated cysts found within the medulla of bones
Associated with cortical expansion
Chambers filled with blood/ serum

PAINFUL
Pathological fractures

*Curettage and bone grafting

The clues are in the name - aneurysmal - think blood and expansion

Question 5

Giant cell tumour

What is it, where is it found, management

Answer 5

BENIGN 
Contain multi-nucleated giant cells
Translocation between chromosome 1 and 2 
Soap bubble appearance on x-ray 
Hemosiderin seen histologically 

Knee and distal radius most commonly

PAINFUL
pathological fractures

*Excision/ joint replacement

Question 6

What are giant cell tumours called when they occur in the knee?

Answer 6

Pigmented villonodular synovitis (PVNS)

Question 7

Fibrous dysplasia

What is it, where is it found, management

Answer 7

BENIGN
Lesions of fibrous tissue and immature bone
Bone is wider with thinned cortices

Adolescence
Genetic mutation in G protein signalling

Any bones - mostly head and neck

Stress fractures
Deformities - E.g Shepherd’s crook deformity

*Bisphosphonates

Question 8

Angular deformities are associated with which benign bone tumours?

Answer 8

Fibrous dysplasia

Defective mineralisation causes angular deformities

Question 9

Osteoid osteoma

What is it, where is found, management

Answer 9

BENIGN
Small nidus of immature bone

Adolescence

INTENSE CONSTANT PAIN WORSE AT NIGHT

May resolve with time

Bone scan and CT to confirm diagnosis

*NSAIDs

Question 10

Name 7 BENIGN bone tumours

Answer 10

Osteochondroma 
Simple bone cyst 
Aneurysmal bone cyst 
Giant cell tumour 
Enchondroma 
Fibrous dysplasia 
Osteoid osteoma

Question 11

Name 4 MAGLIGNANT bone tumours

Answer 11

Osteosarcoma
Chondrosarcoma
Fibrosarcoma
Ewing’s sarcoma

Question 12

Osteosarcoma

What is it, where is it found, management

Answer 12

MALIGNANT
Bone producing bone tumour
Most common form of primary one tumour
Mutations in Rb

Pulmonary metastasis

Adolescence

Mostly bones around the knee, also long bones and pelvis

*Chemotherapy

Question 13

Chondrosarcoma

What is it, where is it found, management

Answer 13

MALIGNANT
Cartilage producing bone tumour

Large and slow to metastasise

Pelvis and proximal femur

*Unresponsive to chemotherapy and radiotherapy

Question 14

Fibrosarcoma

What is it? With which condition is it associated?

Answer 14

Rare malignant bone tumour

Only really occurs if bone is abnormal E.g Paget’s Disease

Question 15

Ewing’s sarcoma

What is it, where is it found, management

Answer 15

MALIGNANT

Adolescence

Onion skin appearance

Fever, warm swelling

Long bones - esp femur

*Radiotherapy/ chemotherapy

Question 16

Which genetic abnormality is Ewing’s sarcoma associated with?

Answer 16

t11;22 translocation involving EWS gene on chromosome 22

Question 17

Which malignant bone tumour is associated with an ‘onion skin appearance’ radiologically?

Answer 17

Ewing’s sarcoma

Question 18

Which bone tumour is sometimes misdiagnosed as osteomyelitis?

Answer 18

Ewing’s sarcoma

This is because it may present with fever, raised inflammatory markers and a warm swelling

Question 19

Which malignant bone tumour belongs to the group the ‘small round blue cell tumours’?

Answer 19

Ewing’s sarcoma

Question 20

Which tumours commonly metastasise to bone?

Try name 5

Answer 20

Breast 
Prostate 
Lung 
Renal cell 
Thyroid

Question 21

What is a ganglion cyst?

Answer 21

Out-pouching from joints/tendon sheaths

May occur due to underlying joint damage and arthritis

Well-defined, firm and transilluminate

Not truly cysts as they don’t have an epithelial lining

Question 22

What is bursitis?

Answer 22

Inflammation of the bursa which are fluid sacs that surround joints

Bursa prevent friction

Occur after repeated pressure/ trauma

Question 23

What are sebaceous cysts?

Answer 23

Subcutaneous lesions

Lined by squamous epithelium which produces lots of keratin

Painless and slowly increase in size

Question 24

What is an abscess?

Answer 24

Collection of neutrophils and infective cellular debris

Question 25

‘Progressive ossification at a site of injury’

What does this describe?

Answer 25

Myositis ossificans

Question 26

‘Rapid growth of a lesion after trauma’

What does this describe?

Answer 26

Nodular fasciitis

Question 27

What is osteochondritis and what age group does it affect?

Answer 27

Inflammation of cartilage or bone due to repetitive stress

Bleeding and oedema within the bone results in capillary compression which can cause necrosis

Occurs in children and adolescence

FH can be relevant

Question 28

Name 4 site which are affected by avascular necrosis

Answer 28

Femoral head
Head of the humerus
Scaphoid
Talus

Question 29

What is meant by ‘creeping substitution’ ?

Answer 29

An attempt to repair dead bone in which the dead bone is encircled by new bone and eventually replaced

Question 30

Name some risk factors for AVN

Answer 30

Alcohol
Steroids
Hyperlipidaemia
*These mobilise fat into the circulation which can sludge up the capillary system and promote coagulation

Thrombophilia
Sickle cell disease
Antiphospholipid deficiency in SLE
*Increased coagulability

Decopression sickness (Caisson's disease) 
*Nitrogen gas bubbles in the circulation