CORTEXT 1 - Basic Sciences PATHOLOGY

Question 1

Which is more common - primary bone tumours or metastatic cancer affecting the skeleton?

Answer 1

Metastatic cancer affecting the skeleton

Question 2

List different types of benign bone tumours

Answer 2

Osteochondroma (commonest)
Enchondroma (lucent or patchy, sclerotic)
Simple bone cyst
Aneurysmal bone cyst (pain, cortical expansion and destruction)
Giant cell tumour (soap bubble XR)
Fibrous dysplasia (shepherds crook, biphosphates for pain)
Osteoid Osteoma (sclerotic halo)

NB Brodie’s abscess and Hyperparathyroidism can also present with lytic lesion of bone.

Question 3

Red flags for bone tumours

Answer 3

Constant severe pain, usually worse at night
Systemic red flags
Age >60 or <25 with unexplained symptoms

Question 4

List some signs of malignant primary bone tumours displayed on an X-ray

Answer 4

Cortical destruction 
Periosteal reaction (raised periosteum producing bone) 
New bone formation 
Extension into surrounding soft tissue envelope

Question 5

What is the most common type of primary bone tumour?

Answer 5

Osteosarcoma (bone producing)

Question 6

What is the most common presentation of Osteosarcoma?

Answer 6

Adolescence and early adulthood
Presents most commonly (60%) involving the knee
10% already have pulmonary mets @ time of diagnosis

Question 7

Features of Chondrosarcoma

Answer 7

Cartilage producing primary tumour 
Mean age 45 yo 
Large, slow to met. 
Pelvis or proximal femur 
Non-radiosensitive including chemo adjuvant

Question 8

When do Fibrosarcoma commonly occur?

Answer 8

In abnormal bone i.e. bone infarct, fibrous dysplasia, post irradiation, Paget’s disease.

Question 9

Features of Ewing’s Sarcoma

Answer 9

Tumour of primitive cells in marrow
Ages 10-20 most commonly
Fever, raised inflammatory markers, warm swelling
Often misdiagnosed as Osteomyelitis
Radio and chemo sensitive, poor prognosis

Question 10

What is the treatment for primary bone tumours?

Answer 10

Surgical removal of tumour and surrounding tissue

Adjuvant chemo and radio used if appropriate

Question 11

What staging investigations are used for primary bone tumours?

Answer 11

Bone scan
CT chest

Biopsy for histological diagnosis and grading prior to surgery also

Question 12

Where are common sites of primary bone lymphoma?

Answer 12

Pelvis

Femur

Question 13

What is the typical presentation of Myeloma?

Answer 13

Age 45-65 
Weakness 
Back pain 
Bone pain 
Fatigue 
Weight loss 
Anaemia and/or recurrent infection 
Sometimes also pathological fracture

Question 14

How is Myeloma diagnosed?

Answer 14

Plasma protein electrophoresis (high paraprotein) and Bence Jones protein assay (morning urine)

Question 15

What primary malignant tumours commonly metastasise to bone?

Answer 15

Commonest - Breast carcinoma (blastic or lytic)
Prostate carcinoma (sclerotic)
Lung carcinoma (lytic)
Renal cell carcinoma (vascular lytic blow out mets, bleed)
Thyroid adenocarcinoma

Question 16

Commonest sites of secondary bone mets?

Answer 16

Vertebra 
Pelvis 
Ribs 
Skull 
Humerus 
Long bones of lower limb

Question 17

Red flags present - what investigations do you do?

Answer 17

1. X-ray

If lesion is found…
2. Bone scan for primary lesion exclusion

If multiple mets found..
3. Seek primary tumour e.g. breast/PR exam, CXR, bloods (incl. serum calcium), LFTs, plasma protein electophoresis, U&Es.

Question 18

Types of soft tissue swelling

Answer 18

Diffuse - synovitis, oedema
Local - inflammatory (bursitis, rheumatoid), infection (abscess), cystic lesions (ganglion, meniscal, Baker’s), neoplasms (benign and malignant)

Question 19

Features of benign vs malignant soft tissue neoplasm

Answer 19

Benign - small, fluctuation in size, cystic, well defined, fluid filled, or soft/fatty

Malignant - >5cm, rapid growth, solid, ill-defined, irregular surface, associated lymphadenopathy, systemic upset

Question 20

What is the most common benign soft tissue tumour?

Answer 20

Lipoma

Question 21

What are the different types of Sarcoma and their origins?

Answer 21

Angiosarcoma - blood vessels 
Fibrosarcoma - fibrous tissue 
Liposarcoma - fat 
Rhabdomyosarcoma - skeletal muscle 
Synovial Sarcoma - synovial lining of joints or tendons

Question 22

What is a ganglion cyst?

Answer 22

cyst occurring around a synovial joint or tendon sheath, sometimes as a result of a herniation.

Well defined, firm, readily transilluminate.

Question 23

What is Bursitis?

Answer 23

Inflamed bursae.

May be caused by bacterial infection, gout, or inflammatory (repeated pressure or trauma)

Examples - Bunions (medial 1st metatarsal head in hallux valgus), Pre-patellar and Olecranon.

Question 24

What is a sebaceous cyst?

Answer 24

implantation dermoids

Question 25

Common causes of abscesses on a limb

Answer 25

Cellulitis
Bursitis
Penetrating wounds
Infected sebaceous cyst

All require drainage.

Question 26

What is the common end result of Osteochondritis and Avascular Necrosis?

Answer 26

An area of bone undergoes localised necrosis as a result of ischaemia from a reduction in blood supply

Question 27

What is avascular necrosis (AVN), and where does it commonly occurs?

Answer 27

Ischaemic necrosis of bone, usually in adults.

Common sites:
femoral head
femoral condyles
head of humerus
capitellum
proximal pole of scaphoid
proximal parts of the talus.

Question 28

Causes of AVN

Answer 28

Secondary to fracture
Idiopathic 
Alcoholism or steroid abuse (due to alteration of fat metabolism)
Primary hyperlipidaemia 
Thrombophilia or sickle cell disease 
Caisson's disease (deep sea diving)

Question 29

How does AVN progress?

Answer 29

Bone necrosis
Patchy sclerosis
Subchondral collapse
Secondary OA (or deterioration of primary)

Question 30

Treatment of AVN?

Answer 30

Stage dependent -
No collapse of articular surface = fluoroscopy and drilling to decompress

If articular collpase = joint replacement (fusion considered in wrist or foot)