1.06 - Neoplasia Flashcards
What does the term tumour mean?
Swelling
Can be non-neoplastic (such as caused by inflammation or infection) or can be neoplastic
What does neoplasm mean?
“New Growth”
A neoplasm is a an abnormal mass of tissue, the growth of which exceeds and is uncontrolled with that of the normal tissues and persists in the same excessive manner after cessation of the stimuli which evoked the changes
Believed that these lesions arise due to the accumulation of somatic mutations.
What does the term oncogenesis mean?
The process of forming a tumour
What do the terms benign and malignant mean?
Bening: “Good natured”. However, benign tumours can, depending on location, cause death.
Malignant: “Very Harmful”
What are some gross features that we can use to distinguish between benign and malignant neoplasms?
Structure Rate of Growth Invasive Growth Disseminated growth by metastasis Of these features, metastasis is a unique feature of malignant neoplasms. Benign neoplasms never metastasise
What are the cytological features of Malignant Cells?
Variable cell size and shape (Cellular Pleomorphism)
Variable nucleus size and shape (Nuclear Pleomorphism)
Increased Nuclear:Cytoplasmic ratio
Hyperchromatic Nuclei
Increased mitosis and abnormal mitosis
Tumour Giant Cells
Do Benign cells differ compared to Malignant cells with respect to the cytological features of malignant cells.
They might show some or all but not to the same extent to that in Malignant cells.
What is Cellular Pleomorphism?
A Cytological feature of malignant cells
Normal cells show uniform size and shape whereas malignant cells vary in their size and shape
What is Nuclear Pleomorphism?
A Cytological feature of malignant cells.
Normal cells have uniform nuclear size and shape whereas malignant nuclei will vary in size and shape
What is Increased Nuclear:Cytoplasmic Ratio?
A Cytological feature of malignant cells
Normal is 1:4-1:6.
Ratio may approach 1:1 in malignant cells
What is Hyperchromatic DNA?
A Cytological feature of malignant cells
Increased intensity of the nuclear stain in malignant cells due to increased DNA
What is Increased and Abnormal Mitosos?
A Cytological feature of malignant cells
The mitotic rate is increased and abnormal in malignant cells compared to normal cells
What are Tumour Giant Cells?
A Cytological feature of malignant cells.
Cells that have duplicated their DNA but have failed to separate completely. A number of cells in one!
Compare Malignant and Benign neoplasms with respect to the arrangement of cell to each other.
Benign - orderly
Malignant - disordered
Compare Malignant and Benign neoplasms with respect to their growth & movement
Benign - tend to grow by expansion and often associated with a capsule
Malignant - tend to infiltrate. “Penetrate with hostile intent”
Define: Differentiation
Extent to which cells resemble normal counterpart (morphologically and functionally)
Can be graded as Well, Moderately or Poor.
Well differentiated: resemble cell of origin
Poorly differentiated: largely different to cell of origin
Define: Anaplasia
Lack of differentiation. i.e. Do not bear any resemblance to the normal cells, whether in structure or function.
Describe the Rate of Growth of Benign and Malignant neoplasms
Benign are slow growing
Malignant are fast growing
Rate of growth correlates with blood supply and differentiation
Fast growing neoplasms may undergo central necrosis due to rapid growth (will appear dark and light on imaging due to the necrosis)
Describe Invasion of Malignant and Benign neoplasms
Invasion is a reliable feature of malignancy
It means neoplastic cells have moved through the basement membrane.
Malignant neoplasms invade and destroy the normal tissue
Malignant neoplasms may appear macroscopically capsulated but microscopically finger like invasion is seen
Benign neoplasms do no invade (they grow by expansion and show a capsule, however lack of a capsule does not always indicate malignancy)
Define: Metastasis
A neoplasm implant discontinuous from the primary neoplasm