Pathology of Neoplasia
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Pathology of Neoplasia
Vet Med - Module 12
What are the direct systemic effects of a tumour on the host?
Space occupying effect, erosion of vessels (acute haemorrhage) and emboli into vessels (cause infarcts at distant sites)
What are the indirect systemic effects on the host?
List three examples of paraneoplastic syndromes
What is cachexia?
Disproportionate thinnes in animals with malignant tumours. Animal will lose both fat and muscle.
True or false: extra calories reverse the catabolic state of cachexia?
What paraneoplastic syndrome causes hypercalcaemia?
Production of parathyroid hormone related protein (PTHrP) by tumours
What type of tumours produce PTHrP?
Apocrine adenocarcinoma of anal sac in dog, lymphoma, multiple myeloma
What are the clinical signs of hypercalcaemia?
Muscle weakness, cardiac arrhythmia, anorexia, vomiting, renal failure
What is an a) direct b) paraneoplastic cause of hypoglycaemia?
a) insulinoma (tumour of pancreas islet B-cells)
b) other tumour cell types that produce insulin like substances
What are the clinical signs of hypoglycaemia?
Lethargy, incoordination, muscle weakness, seizures
List some of the important viral induced tumours in veterinary species
Feline leukaemia virus - lymphoma, leukaemia
Bovine leukaemia virus - lymphoma, leukaemia
Feline immunodeficiency virus - lymphoma
Jaagsiekte sheep retrovirus - pulmonary carcinomas
Avian leukosis virus - lymphomas, leukaemias
Marek's disease - lymphoproliferative disease
What is another name for Jaagsiekte?
Ovine pulmonary carcinoma
What is the test for Jaagsiekte?
Wheelbarrow test - tip the sheep onto its front legs and if fluid exits through the nose the sheep has Jaagsiekte
Where is there a high incidence of Jaagsiekte?
Scotland, South Africa and Peru
What are the microscopic findings of Jaagsiekte?
Bronchioloavleolar carcinoma, possible sequelae (bronchopneumonia, abscesses, fibrous pleural adhesions), metastases
What causes equine sarcoids?
Non-productive infection by bovine papilloma virus
What are equine sarcoids?
Locally aggressive, non-metastatic fibroelastic skin tumours
What is the most common type of tumour in domestic animals?
What causes lymphoma in a) cattle b) cats?
a) bovine leukaemia virus, sporadic bovine lymphoma
c) feline leukaemia virus
What are the two types of canine lymphoma?
B or T cell lymphoma
How do you tell if a dog has a B or T cell lymphoma?
Immunohistochemistry. A brown stain indicates a positive result. The marker for T cell lymphoma is CD3 and the marker for B cell lymphoma is CD79a.
What types of dogs are susceptible to the following tumours? a) lymphoma/sarcoma b) malignant histiocytosis c) haemangiosarcoma d) osteosarcoma e) mast cell tumour (skin)
b) bernese mountain dog
d) Giant breeds, GSD, boxer, rottweiller
e) boxer, bulldog, retriever
List some of the features of malignancy
High mitotic index/abnormal mitoses
High N:C ratio
Absence of encapsulation
Lack of differentiation
What are the differentials for canine round cell tumours?
Canine cutaneous histiocytoma
Mast cell tumour
(Transmissable venereal tumour)