Presentations & diagnosis of neoplasia Flashcards
How are neoplastic lesions named?
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
What is the suffix of a benign tumour
-oma (e.g. adenoma)
What is the suffix of a malignant tumour
-sarcoma or -carcinoma depending on cell origin
What are some common benign tumours in dogs?
What are some common malignant tumours of dogs?
What are some common malignant tumours in cats?
Mast cell tumour
Lymphoma - more commonly internal in cats
Mammary carcinoma
Osteosarcoma
Haemangiosarcoma
Squamous cell carcinoma
What are some common tumours in horses?
What is the most common route of metastasis for sarcomas
Haematogenous
What is the most common route of metastasis for carcinomas
Lymphatic
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 gut will travel to liver first
What is the most common route of metastasis for mesotheliomas & ovarian adenocarcinomas
Transcoelomic
What tumour types commonly metastasise in lungs
What tumour types commonly metastasise in bone
What tumour types commonly metastasise in liver, spleen & kidney
How do cancer cells reach the bone?
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
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 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
What are common presenting signs of neoplasia
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
What direct effects of neoplasia cause clinical signs?
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)
What indirect effects of neoplasia cause clinical signs?
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
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
Give examples of paraneoplastic syndromes that affect the GIT
Give examples of dermatological paraneoplastic syndromes
Give examples of neuromuscular paraneoplastic syndromes
Give examples of endocrine paraneoplastic syndromes
Describe hypercalcaemia of malignancy
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
What are some other common paraneoplastic syndromes?
What are the types of biopsy?
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
What is the difference between incisional & excisional biopsy?
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)
What are the pros & cons of FNA?
What are the pros & cons of surgical biopsy?
In what situations is a biopsy not encouraged?
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
