Characteristics of Tumours Flashcards
What is a tumour?
A swelling or a mass of any kind
What is neoplasia?
New, uncontrolled growth of cells that is not under physiologic control. Can be benign or malignant.
What is cancer?
A generic term for a large group of diseases characterized by the growth of abnormal cells beyond their usual boundaries that can then invade adjoining parts of the body and/or spread to other organs.
Hallmarks of cancer
- Environmental factors causing mutations + inherited genetic mutations
- Mutations accumulate
- Hallmarks of cancer accumulate
- Malignant cell
What sets cancer apart from benign neoplasms?
The invasion/spread to other organs
What is embryological histogenesis?
The formation of differentiated tissues from undifferentiated endoderm, ectoderm and mesoderm cells.
What is tumour histogenesis?
Tumours are named according to the tissues from which they arise
What are tumours arising from the endoderm (internal layer) called? E.g. tumour arising from the epithelial lining of digestive tract?
Carcinoma (either squamous cell carcinoma or adenocarcinoma)
What are tumours arising from the mesoderm (middle layer) called? E.g. skeletal muscle cell?
Sarcoma –> e.g. leiomyosarcoma is a rare type of cancer that affects smooth muscle tissue
What are tumours arising the ectoderm (outer layer) called? E.g. from pigment cells?
Melanoma
What is differentiation?
the extent to which a neoplasm resembles its tissue of origin:
- Well-differentiated = neoplasm closely resembles tissue of origin
- Moderately-differentiated= neoplasm shows some resemblance to tissue of origin
- Poorly-differentiated= neoplasm does not resemble tissue of origin
What is anaplasia?
A neoplasm that is poorly differentiated and highly pleomorphic
What is pleomorphic?
Having variation in the size and shape of cells or their nuclei.
Most common cancers in females
Why are non-melanoma skin cancers typically excluded from data?
Although they carry a high incidence, their mortality risk is low (squamous cell carcinoma and basal cell carcinoma)
Female deaths from cancer
Most commoon cancers in males?
Male deaths from cancer?
Invasion: benign vs malignant?
Benign: Neoplasm does NOT invade surrounding tissues
Malignant: Neoplasm DOES invade surrounding tissues
Mets; benign vs malignant?
Benign: do not metastasise
Malignant: may metastasise; lymphatic, haematogenous, direct seeding
What is metastasis?
The development of secondary malignant growths at a distance from a primary site of cancer.
What is often the first site of metastasis?
Lymph nodes
What is direct seeding?
Malignant neoplasm penetrates into a natural body cavities
Rate of growth; benign vs malignant?
Benign: slow rate of growth
Malignant: fast rate of growth (division exceeds cell death)
Differentiation; benign vs malignant?
Benign: well differentiated
Malignant: can be well differentiated, moderately or poorly differentiated or even anaplastic
Prognosis; benign vs malignant?
Benign; rarely fatal (unless CNS as can lead to compression of brain tissue)
Malignant: often fatal
What are the 3 main categories of tumour complications?
- Effects of primary tumour
- Effects of distant metastases
- Paraneoplasic syndromes
What are the main effects of a primary tumour?
- Invasion into and replacement of normal tissues/organs –> failure of that organ to function (e.g. bone marrow, liver)
- Pressure on normal tissue –> failure of that organ to function (especially in brain)
- Invasion into blood vessels –> bleeding
- Pressure on the blood vessels –> ischaemia
- Pressure/invasion into nerves –> loss of nerve function/pain
- Grow into a lumen –> obstruction (e.g. colon)
What are distant metastases?
When a cancer spreads to different parts of the body forming new (secondary) tumours.
What are the effects of distant metastases?
- Invasion into tissues
- Pressure on tissues
- Invasion into blood vessels etc
What are paraneoplastic syndromes?
Signs and symptoms that are NOT related to local effects of the primary or metastatic tumours
What do paraneoplastic syndromes develop as a result of?
- Proteins/ hormones secreted by tumour cells
- Immune cross reactivity between tumour cells and normal tissues
What is a stroma?
- Cells that support the parenchyma
- Organ = parenchyma + stroma
What is parenchyma?
Cells that perform actual function of an organ eg cells that do gas exchange (pneumocytes) in the lungs, cells that contract in the heart (myocytes)
Stroma contain many cell types including…?
- Blood vessels
- Fibroblasts (+ the collagen they make)
- Immune cells
What is desmoplasia?
Desmoplasia refers to growth of dense connective tissue or stroma
What cells are found in tumour stroma?
Tumour stroma composed of the same cells types as normal stroma, but the stromal cells have different functions; blood vessels, fibroblasts, immune cells
With this colonic tumour, what local effect is the patient at most risk of developing?
Bowel obstruction
Which arrow is pointing to tumour stroma?
2
- 3 is normal colonic epithelium and the gaps in between is normal stroma
What is the grade of a tumour?
How well/poorly it is differentiated
