Basic Science - Pathology

Question 1

What is the commonest benign bone tumour?

Answer 1

Osteochondroma

Question 2

What is an osteochondroma and what is the treatment of a growing or painful lesion?

Answer 2

Bony outgrowth externally with cartilagenous cap

Excisional biopsy

Question 3

What is the cause of multiple osteochondroma?

Answer 3

Autosomal dominant hereditary disorder

Question 4

Where do enchondroma occur?

Answer 4

Within - intramedullary and at metaphysis

Anatomically - Femur, humerus, tibia and small bones of hand and feet

Question 5

What are the consequences of an enchondroma?

Answer 5

Can weaken bone and result in pathologic fracture

Question 6

What is the treatment for a enchondroma if there has been a fracture or risk of one?

Answer 6

Curretage and bone graft

Question 7

What is a simple bone cyst?

Answer 7

Single fluid filled cyst in bone = Growth defect from the physis, therefore metaphyseal in long bones

Question 8

What is an aneurysmal bone cyst?

Answer 8

Multiple chambered filled with blood = arteriovenous malformation. Lesion locally agressive and causes cortical destruction and pain

Question 9

Where do aneurysmal bone cysts occur?

Answer 9

Metaphyses of long bones, flat bones and vertebral bodies

Question 10

What is a giant cell tumour of the bone?

Answer 10

‘Soap bubble’ X ray appearance, locally aggressive/ destructive tumours of multi nucleated giant cells arising in metaphyseal region normally. Can also involve epiphysis ans subchondral bone

Question 11

What is the treatment of a GCT of bone?

Answer 11

Intralesional excision with phenol, bone cement or liquid nitrogen used to reduce recurrence

Cortical destruction can = joint replacement

Question 12

What is a complication of GCT?

Answer 12

Metastases to lung causing benign pulmonary GCT

Question 13

What is fibrous dysplasia?

Answer 13

Lesions of fibrous tissue and immature bone caused by genetic mutation.

In adolescence

Can cause defective mineralisation = angular deformities. Bone is also wider with thinner cortices

Question 14

What is the consequences of fibrous dysplasia?

Answer 14

Shepherds crook deformity of proximal femur if involved

Stress fracture

Question 15

Treatment of fibrous dysplasia?

Answer 15

Bisphosphonates for pain

Internal fixation stabilising and cortical bone graft for pathological fracture

Question 16

What is osteoid osteoma?

Answer 16

A site of immature bone surrounded by intense sclerotic halo

Adolescence

Occurring at proximal femur, diaphysis of long bones and vertebrae

Causes intense pain, worse at night due to inflammation

Question 17

Treatment of osteoid osteoma?

Answer 17

NSAIDS for pain

Some require CT guided radioablation or en bloc excision

Question 18

What is a Brodies abscess?

Answer 18

Lytic bone lesion caused by subacute osteomyelitis

Question 19

What is a Brown tumour?

Answer 19

Lytic bone lesion caused by hyperparathyroidism

Question 20

What is the cause of enchondroma?

Answer 20

Failure of normal enchondral ossification

Question 21

What are the RED FLAGS of any metastatic bone tumour?

Answer 21

Constant pain, ?severe and worse at night

Systemic - weigh loss, fatigue and loss of appetite

Be aware of older and younger patients

Question 22

What is the investigation done initially if suspicious of bone malignancy ?

Answer 22

X Ray

Question 23

In whom are primary bone tumours likely to occur?

Answer 23

Under 25’s

Question 24

What feature would mandate urgent referral ?

Answer 24

Substantial, ill defined bony swelling

Question 25

What would a primary bone tumour show on X ray?

Answer 25

Cortical destruction, periosteal reaction, new bone formation combined with lysis from destruction and extension into surrounding tissue

Question 26

What is the commonest primary bone cancer?

Answer 26

Osteosarcoma

Question 27

Site of osteosarcoma?

Answer 27

60% involve bones around knee Other sites = proximal femur and humerus + pelvis

Question 28

What is the method of spread of osteosarcoma?

Answer 28

Haematogenous + lymphatic in some cases

Question 29

What adjuvant treatment can be used for osteosarcoma?

Answer 29

Chemotherapy, NOT radiotherapy

Question 30

Where will patients with osteosarcoma often have mets?

Answer 30

Pulmonary

Question 31

What is Ewings Sarcoma?

Answer 31

Malignant tumour of primative cells in marrow Is radio and chemo sensitive

Question 32

What can be a presentation of Ewings sarcoma?

Answer 32

Much like osteomyelitis Fever, raised inflammatory markers and warm swelling

Question 33

What is the definitive treatment of primary bone cancer?

Answer 33

Surgery for removal - margin of 3-4 cm + cuff of muscle Staging through CT and MRI and biopsy Often limb salvage afterwards involving joint reconstruction with large replacements to counteract bone loss

Question 34

What cancers will tend to metastasise to bone?

Answer 34

Breast, prostate, lung, renal cell and thyroid adenocarcinoma

Question 35

Features of breast cancer bone mets?

Answer 35

Can be lytic ( black on x ray) or sclerotic/ blastic ( white on X ray)

Question 36

Feature of prostate cancer bone mets?

Answer 36

Sclerotic lesions Radiotherapy and hormone treatment can reduce fracture risk Osteoblastic activity means fractures more likely to heal

Question 37

Features of lung cancer bone mets?

Answer 37

Lytic lesions

Question 38

Features of renal cell carcinoma bone mets?

Answer 38

Large, very vascular lytic lesions Single bone met + resectable primary tumour can = cure by surgery

Question 39

How can a primary bone tumour be excluded if lesion found on X ray?

Answer 39

By bone scan or ?MRI

Question 40

What would indicate impending pathological fracture and therefore intervention?

Answer 40

Pain on weight bearing especially Over 50% bone diameter Cortical thinning At risk area

Question 41

What is skeletal stabilisation?

Answer 41

Insertion of long rods/ intramedullary nails or joint replacement if destruction of joint Any surgery = HIGH risk DVT so prophylaxis must be taken

Question 42

How can spinal cord compression be treated?

Answer 42

Usually in advanced spinal mets By radiotherapy or anterior or posterior surgical decompression

Question 43

What is a ganglion cyst?

Answer 43

Cyst around synovial joint or the synovial tendon sheath caused by herniation of weak portion of joint capsule

Question 44

What are types of ganglion cyst?

Answer 44

Developmental - i.e. juvenile Bakers's cyst Resulting from joint damage or arthritis - i.e. Adult Baker's cyst, mucous cyst of DIP joint, wrist ganglion

Question 45

What are the features of a ganglion cyst?

Answer 45

Well defined, quite firm and transilluminate

Question 46

What is a bursitis?

Answer 46

Inflamed bursae occurring due to repeated pressure and trauma. Can also be caused by gout and a bursal abscess can be caused by bacterial infection. Thickened bursal sack can be left after inflammation subsides

Question 47

What sites are prone to avascular necrosis (AVN)?

Answer 47

``` Femoral head Femoral chondyles Head of humerus Capitellum Proximal pole of scaphoid Proximal part of talus ```

Question 48

Causes of AVN

Answer 48

``` Fracture Alcoholism and steroid use or abuse Primary hyperlipidaemia Thrombophilia Sickle cell disease Antiphospholipid in SLE Caisson's disease ```

Question 49

How does lipid accumulation cause AVN

Answer 49

Increased fat in circulation = increased marrow fat content compressing venous outflow from bone

Question 50

What is sequelae of AVN?

Answer 50

``` Necrosis Patchy sclerosis Subchondral collapse Irregularity of articular surface Secondary osteoarthritis ```

Question 51

Treatment of osteoarthritis?

Answer 51

If no articular collapse in an amenable site - drilling under fluroscopy to decompress bone Articular collapse = joint replacement Fusion? in wrist or ankle and foot