Presentations and diagnosis of neoplasia Flashcards
How are neoplastic lesions named?
First half of tumour name (prefix) tells you the cell or tissue of origin
Second half of tumour name (suffix) tells you if it is benign or malignant
Benign: -oma e.g., haemangioma
Malignant: -sarcoma or -carcinoma e.g., haemangiocarcoma
What are benign and malignant tumours from glandular epithelium called?
Benign - adenoma
Malignant - adenocarcinoma
Give examples of common benign tumours in dogs
What tumour is this?
lipoma
What tumour is this?
papilloma - tumour of the protective epithelium
What tumour is this?
sebaceous adenoma
Give examples of common malignant tumours in dogs
What tumour is this?
mast cell tumour
- primarily present on skin
- release histamine => inflammation at site
What tumour is this?
lymphoma
What tumour is this?
mammary carcinoma
- hard and nobbly
What tumour is this?
osteosarcoma
What tumour is this?
haemangiosarcoma:
- commonly a splenic mass
Give examples of common malignant tumours of cats
Mast cell tumour
Lymphoma - more commonly internal in cats
Mammary carcinoma
Osteosarcoma
Haemangiosarcoma
Squamous cell carcinoma
What tumour is this?
squamous cell carcinoma
- common in white cats/sections of white
Give examples of common tumours of horses
What tumour is this?
sarcoids
What tumour is this?
squamous cell carcinoma
What tumour is this?
Melanoma
What are metastatic tropisms?
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 the gut will travel to liver first
Which tumours commonly metastasise in lungs?
Which tumours commonly metastasise in bone?
Which tumours commonly metastasise to the liver, spleen, kidney?
Where will prostate cancer commonly metastasise?
Brain
Lungs
Liver
Bone marrow
Why is metastasis important?
90% of cancer deaths are due to cancerous growths at sites in the body distant from the primary tumour
Once cancer has metastasised, it limits treatment options and prognosis
What are the common presenting signs of neoplasia?
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
Can be vague and non-specific e.g., just not quite themselves
What direct effects of neoplasia cause clinical signs?
Space occupying lesions:
- compression e.g., brain tumour => neurological signs
- obstruction e.g., tumour obstructing GIT => vomiting, anorexia
- pain e.g., osteosarcoma => lameness
Bleeding:
- Tumour ulcerates - chronic low-level bleeding e.g., gastric carcinoma => malaena (black poo), haematemesis (blood in vomit), lethargy
- Tumour ruptures - acute haemorrhage e.g., splenic haemangiosarcoma => collapse
Describe the indirect causes of clinical signs in neoplasia
Effusions:
- pericardial
- pleural
- abdominal
Infection:
- usually secondary to necrosis
Paraneoplastic syndromes:
- caused by products of tumour cells, not the tumour mass
Why is it important to identify paraneoplastic syndromes?
Can be life-threatening
May help diagnose the primary tumour
Can affect response to treatment
Affect quality of life
Give examples of paraneoplastic syndromes that affect the haematological system
Anaemia
Thrombocytopaenia - Several mechanisms:
- increased consumption
- increased sequestration
- immune mediated destruction
Coagulopathies:
- hypercoagulability
- Disseminated intravascular coagulation (DIC)
Give examples of paraneoplastic syndromes that effect the GIT
Ulceration:
- mast cell tumours => increase histamine => increased gastric acid secretion => ulceration
- presents as melaena and haematemesis
Give examples of dermatological paraneoplastic syndromes
Give examples of neuromuscular paraneoplastic syndromes
give examples of endocrine paraneoplastic syndromes
Hypercalcaemia = assume cancer until proven otherwise
Describe hypercalcaemia of malignancy
Cancer is the most common cause of hypercalcaemia in dogs (and top 3 in cats)
Caused by parathyroid hormone-related protein (PTHrP) produced directly by tumour cells
Acts on bones and kidneys to stimulate calcium release into blood
What other common paraneoplastic syndromes are there?
What is hypertrophic osteopathy?
rapid periosteal new bone growth affecting distal limbs. Most commonly associated with lung tumours (primary or metastatic)
What are the different types of biopsy?
Fine needle aspiration (FNA) - for cytology
Surgical biopsy (incisional and excisional) - for histopathology
What is the difference between incisional and excisional biopsy?
Incisional - take a small piece of mass before surgical removal
Excisional - remove whole mass and send for labs
When are incisional and excisional tumours favoured?
Incisional best for planning surgery afterwards so can determine margins etc.
Excisional best when tumour type is highly suspected and pre-op biopsy will not affect outcome e.g. bleeding splenic mass
What are the pros and cons of FNAs
What are the pros and cons of surgical biopsy?
In what situations is a biopsy not encouraged?
When knowledge of the tumour type will not influence the treatment plan
e.g. a bleeding splenic mass is a 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
