ONCOLOGY - Neoplasia Flashcards
What is oncology?
Oncology is the study of neoplasia
What is a hamartoma?
A hamartoma is chaotically arranged tissue
What is a choristoma?
A choristoma is chaotically arranged tissue in an abnormal location
What are four changes that may precede neoplasia?
Hypertrophy
Hyperplasia
Metaplasia
Dysplasia
What are the two main categories of veterinary tumours?
Mesenchymal
Epithelial
What is a subgroup of mesenchymal tumours?
Round cell tumours
What are the four main differentials of round cell tumours?
Lymphoid cells
Mast cells
Plasma cells
Histiocytes
What is leukaemia?
Leukaemia is a malignancy derived from circulating blood cells or their precursors
What are the suffixes used to describe benign and malignant mesenchymal tumours?
Benign: ends with ‘oma’
Malignant: ends with ‘sarcoma’
What is the term used to describe benign lymphoid tumours?
This is a trick question as there are no benign lymphoid tumours, both lymphoma and lymphosarcoma are malignant lymphoid tumours
What are the suffixes used to describe benign and malignant epithelial tumours?
Benign: ends with ‘oma’
Malignant: ends with ‘carcinoma’
What is a squamous papilloma?
Squamous papillomas are warts
What are the four features used to differentiate between benign and malignant tumours?
Differentiation
Growth rate
Local invasion
Metastasis
What is anaplasia?
Anaplasia is the complete loss of cell differentiation
Why can neoplastic cells often have some of the same features as embryonic cells?
- Normal cells may de-differentiate as they evolve into neoplastic cells leading to the re-surfacing of primitive structures
- Tumours may arise from the small population of pluripotent stem cells present within adult tissues
In terms of the cell cycle, what are the main differences between tumour cells and normal cells?
Neoplastic cells spend very little time in G0 and do not undergo cell cycle arrest when there are mutations in their DNA sequence and thus evolve with genomic instability
Are tumour cells dependent on their host for replication?
No. Tumour cells are independent of the host for replication
What is the latency period in terms of tumours?
The latency period is the time taken for a tumour to become clinically apparent
How many replications does a neoplastic cell need to undergo to form a clinically significant tumour?
30 replications
How many more replications do neoplastic cells need to form a tumour no longer compatible with animal life?
10 more replications
What are four characteristics of benign tumours?
Well differentiated
Slow growth
No true invasion
No metastasis
What are six characteristics of malignant tumours?
Lack of differentiation
Atypical morphology
Anaplasia
Erratic growth
Infiltrative growth
Metastasis
What is Anisocytosis?
Anisocytosis is the term used to describe a variation in cell size
What is Macrocytosis?
Macrocytosis is the term used to describe abnormally enlarged cells
What is Hypercellularity?
Hypercellularity is the term used to describe increased cell exfoliation
What is Pleomorphism?
Pleomorphism is the term used to describe a variation in the size and shape of cells within a given population
What is Macrokaryosis?
Macrokaryosis is the term used to describe abnormally increased nuclear size
What is Anisokaryosis?
Anisokaryosis is the term used to describe variations in nuclear size
What is Multinucleation?
Multinucleation is the term used to describe multiple nuclei within one cell
What is Nuclear moulding?
Nuclear moulding is the term used to describe the deformation of nuclei by adjacent nuclei within the same cell or adjacent cells
What are Macronucleoli?
Macronucleoli is the term used to describe abnormally increased nucleoli size
What are Angular nucleoli?
Angular nucleoli is a term used to describe prominent angular nucleoli
What is Anisonucleoliosis?
Anisonucleoliosis is a term used to describe a variation is nucleoli size
How many cytological features of malignancy need to be identified to classify a tumour as malignant?
Three cytological features of malignancy need to be identified
Both cytology and histology can be used to assess the morphological features of neoplastic cells. What additional components can be assessed using histology?
Margins
Evidence of metastasis
What are three historical features of malignancy?
Increased mitotic figures
Multiple nucleoli
Karyomegaly (abnormal, large nuclei)
Give an example of a tumour commonly seen in white haired animals?
Squamous cell carcinoma (SCC)
What are the three hormones that can be produced by ovarian granuloma cell tumours?
Oestrogens
Androgens
Inhibin
(T/F) Ovarian granuloma cell tumours in large animals are usually malignant
FALSE. Ovarian granuloma cell tumours in large animals are usually benign and completely harmless
How does the secretion of testosterone by ovarian granuloma cell tumours effect mares?
Testosterone secretion by ovarian granuloma cell tumours can lead to mares exhibiting stallion-like behaviours
Why are ovarian granuloma cell tumours in bitches more high risk?
Ovarian granuloma cell tumours in bitches have a higher chance of being malignant or the secretion of progesterone by the tumour can lead to cystic endometrial hyperplasia ultimately leading to a pyometra
What are the two main structural components of tumours?
Parenchyma
Stroma
What is the function of the tumour parenchyma?
The tumour parenchyma is the neoplastic or transformed cellular component of the tumour which determines the biological behaviour of the tumour
What is the function of the tumour stroma?
The tumour stroma is the non-neoplastic, host-derived support tissues essential for tumour growth
What is a scirrhous response?
The scirrhous response is the production of dense collagenous stroma by tumour-associated fibroblasts in response to the secretion of plasma derived growth factor (PDGF) by tumour cells
Describe the three stages of tumour development
- Initiation: Irreversible genetic change introduced by an initiator
- Promotion: Outgrowth of initiated cells in response to specific stimuli
- Transformation and progression: Benign tumours progressively become malignant and metastatic
What is tumour heterogeneity?
Tumour heterogeneity is the sub-clones of neoplastic cells within one tumour
Give four examples of tumour cell sub-clones
Non-antigenic neoplastic cells
Metastatic neoplastic cells
Lower growth factor requirement neoplastic cells
Invasive neoplastic cells
At what diameter do tumours need to carry out angiogenesis to establish their own blood supply?
2mm in diameter
Give an example of an angiogenesis inhibiting factor
Thrombospondin
What triggers feline injection site sarcomas?
Feline injection site sarcomas are triggered by the repeated granulomatous inflammation at an injection site
What are the three tumour metastasis pathways?
Transcoelomic
Haematogenous
Lymphatic
What is transcoelomic metastasis?
Transcoelomic spread refers to the route of tumour metastasis across a body cavity
List three examples of cancers which commonly metastasise via the transcoelomic route
Mesothelioma
Ovarian adenocarcinoma
Pancreatic adenocarcinoma
Which type of tumours favour the haematogenous route of metastasis?
Sarcomas favour haematogenous metastasis
Which type of tumours favour the lymphatic route of metastasis?
Carcinomas favour lymphatic metastasis
What are transmissible tumours?
Transmissible tumours are clonal transmissible cancers that can be spread through direct physical contact
What are two transmissible tumours seen in animals?
Transmissible venereal tumours (TVT)
Devil facial tumour disease (DFTD)
Give an example of a benign tumour that is easily regressed by immunosurveillance
Canine cutaneous histiocytoma
