Cancer Flashcards
Define a tumour
Any kind of mass forming lesion.
May be neoplastic, hamartomatous or inflammatory (e.g. nasal polyps inflammatory lumps in nose).
Define neoplasm
The autonomous growth of tissue which have escaped constraints on cell proliferation
Dysregulated growth
What are the two broad descriptions that we have to describe neoplasms?
Benign - remain localised
Malignant - invade locally/spread to distant sites - this spread is called metastasis
What kind of tumour is a cancer?
Malignant neoplasms
What are the differences in appearance between benign and malignant neoplasms?
benign neoplasm- well contained, smooth round appearance
malignant neoplasm- not well demarcated margins, hard to describe where it starts and ends
What are the 6 hallmark features of neoplastic cells (cancerous)?
Evading apoptosis Sustained angiogenesis limitless replicative potential Insensitivity to anti-growth signals Tissue invasion and metastasis Self-sufficiency in growth signals
Define what is meant by a hamartoma
Tissue is found in the wrong place in an organ
Localised benign overgrowths of one or more mature cells types
ie overgrowth of cartilage tissue in lungs
represent architectural not cytological abnormalities
Why are hamartomas more common in children?
usually caused by genetic abnormalities in important developmental genes.
Define what is meant by heterotopia
Normal tissue being found in parts of the body where they are not usually present
ie pancreas tissue on intestinal wall
Define what is meant by a teratoma
These are tumours derived from germ cells and can contain tissue derive from all three for 3 germ cell layers
They may contain mature and / or immature tissue and even cancers.
(The 3 germ layers are ectoderm, endoderm and mesoderm)
What are the usual stems and suffixes used to describe neoplasms?
Stem = relevant tissue
Suffix
= oma if benign
= sarcoma if malignant
What are exceptions to the normal rules for naming cancers?
All malignant neoplasms Hepatoma - liver Melanoma - melanocytes Mesothelioma - pleural tissue Seminoma - germ cell neoplasm of testis Lymphoma - lymphocytes
What is meant by invasion?
This means direct extension into the adjacent connective tissue and /or other structures e.g. blood vessels.
This is what distinguishes dysplasia/carcinoma in situ from cancer.
Describe how invasion can be used to distinguish between benign and malignant neoplasms
Malignant tumours infiltrate and destroy the surrounding tissue, poorly demarcated
Invasion will often trigger an immune response- so we will see lymphocytes on histology
Most benign tumours grow as cohesive, expansile masses that remain localised to their site of origin (encapsulated)- don’t infiltrate surrounding tissue
Describe how invasion can be used to distinguish between benign and malignant neoplasms
Malignant tumours infiltrate and destroy the surrounding tissue, poorly demarcated
Invasion will often trigger an immune response- so we will see lymphocytes on histology
Most benign tumours grow as cohesive, expansile masses that remain localised to their site of origin (encapsulated)- don’t infiltrate surrounding tissue
Describe what is meant by metastasis
This means spread ,via blood vessels etc, to other parts of the body.
All malignant tumours have the capacity to metastasise
Formation of discontinuous tumour implants at a distance from the main tumour mass
Only gliomas and basal cell carcinomas cannot metastasise
Where does a carcinoma cancer begin?
cancer that begins in the skin or in tissues that line or cover internal organs