Presentations & diagnosis of neoplasia

Question 1

How are neoplastic lesions named?

Answer 1

prefix tells you cell or tissue of origin

Suffix tells you if it is benign or malignant
- Malignant suffix also gives more information about overall cell type of tumour

Question 2

What is the suffix of a benign tumour

Answer 2

-oma (e.g. adenoma)

Question 3

What is the suffix of a malignant tumour

Answer 3

-sarcoma or -carcinoma depending on cell origin

Question 4

What are some common benign tumours in dogs?

Answer 4

Question 5

What are some common malignant tumours of dogs?

Answer 5

Question 6

What are some common malignant tumours in cats?

Answer 6

Mast cell tumour
Lymphoma - more commonly internal in cats
Mammary carcinoma
Osteosarcoma
Haemangiosarcoma
Squamous cell carcinoma

Question 7

What are some common tumours in horses?

Answer 7

Question 8

What is the most common route of metastasis for sarcomas

Answer 8

Haematogenous

Question 9

What is the most common route of metastasis for carcinomas

Answer 9

Lymphatic

Question 10

What are metastatic tropisms?

Answer 10

Cancer cells from different tumour types have favoured sites for colonisation

Dependent on:
- ability of tumour cells to adapt to microenvironment of distant tissues
- layout of circulation e.g., cancer cells in gut will travel to liver first

Question 10

What is the most common route of metastasis for mesotheliomas & ovarian adenocarcinomas

Answer 10

Transcoelomic

Question 11

What tumour types commonly metastasise in lungs

Answer 11

Question 12

What tumour types commonly metastasise in bone

Answer 12

Question 13

What tumour types commonly metastasise in liver, spleen & kidney

Answer 13

Question 14

How do cancer cells reach the bone?

Answer 14

Cancer cells reach bone though vessels of marrow

They adhere to specialised stromal cells coating bone facing marrow

They are attracted by growth factors contained in ECM (organic scaffolding of bone)

Cancer cells activate osteoclasts & osteoblasts at different extents resulting in osteolytic & osteoblastic metastasis

Question 15

Where will prostate cancer commonly metastasise?

Answer 15

Brain
Lungs
Liver
Bone marrow

Question 16

Why is metastasis important?

Answer 16

90% of cancer deaths are due to cancerous growths at sites in body distant from primary tumour

Once cancer has metastasised, it limits treatment options & prognosis

Metastasis is what kills cancer patients
- must identify it to offer most effective treatment options & prevent it through early treatment of primary tumours

Question 17

What are common presenting signs of neoplasia

Answer 17

Often vague & non-specific

Pain
Visible lump(s)
Reduced appetite
Vomiting
Weight loss
Increased drinking
Change in toileting
Change in breathing/cough
Off legs/reluctance to walk
Seizures/neurological changes

Question 18

What direct effects of neoplasia cause clinical signs?

Answer 18

Space-occupying lesion resulting in compromise of function:
- Compression (e.g. brain tumour pressing on normal tissue=> neurological signs)
- Obstruction (e.g. intestinal lymphoma obstructing GIT => vomiting, anorexia)
- Pain (e.g. osteosarcoma causing bone destruction=> lameness)

Bleeding
- Tumour ulcerates- chronic low-level bleeding (e.g. gastric carcinoma => melaena, haematemesis, lethargy)
- Tumour ruptures- acute haemorrhage (e.g. splenic haemangiosarcoma=> collapse)

Question 19

What indirect effects of neoplasia cause clinical signs?

Answer 19

Effusions
- Pericardial (e.g. canine haemangiosarcoma)
- Pleural (e.g. feline mediastinal lymphoma)
- Abdominal (e.g. canine lymphoma)

Infection
- Usually secondary to necrosis(e.g. canine mammary carcinoma)

Paraneoplastic syndromes
- Caused by products of tumour cells, not tumour mass

Question 20

Why is it important to identify paraneoplastic syndromes?

Answer 20

Can be life-threatening
May help diagnose the primary tumour
Can affect response to treatment
Affect quality of life

Question 21

Give examples of paraneoplastic syndromes that affect the haematological system

Answer 21

Question 22

Give examples of paraneoplastic syndromes that affect the GIT

Answer 22

Question 23

Give examples of dermatological paraneoplastic syndromes

Answer 23

Question 24

Give examples of neuromuscular paraneoplastic syndromes

Answer 24

Question 25

Give examples of endocrine paraneoplastic syndromes

Answer 25

Question 26

Describe hypercalcaemia of malignancy

Answer 26

Cancer is most common cause of hypercalcaemia in dogs

Caused by parathyroid hormone-related protein (PTHrP) produced directly by tumour cells

Acts on bones & kidneys to stimulate calcium release into blood

Always take high Ca on biochemistry seriously

Question 27

What are some other common paraneoplastic syndromes?

Answer 27

Question 28

What are the types of biopsy?

Answer 28

Fine needle aspirate (FNA):
- for cytology
- examination of cells that have exfoliated from mass

Surgical biopsy (incisional & excisional)
- for histopathology
- examination of tissue architecture of mass

Question 29

What is the difference between incisional & excisional biopsy?

Answer 29

Incisional
- take small piece of mass before surgical removal
- best for planning surgery afterwards to determine margins etc.

Excisional
- remove whole mass & send for labs
- best when tumour type is highly suspected & pre-op biopsy will not affect outcome (e.g. bleeding splenic mass)

Question 30

What are the pros & cons of FNA?

Answer 30

Question 31

What are the pros & cons of surgical biopsy?

Answer 31

Question 32

In what situations is a biopsy not encouraged?

Answer 32

When knowledge of tumour type will not influence treatment plan
- e.g. bleeding splenic mass is life-threatening emergency that requires surgical removal regardless of tumour type

When the biopsy process may itself cause tumour spread or compromise future treatment
- e.g. bladder transitional cell carcinomas –> seeding metastases