Neoplasia 1 Flashcards
What is neoplasia?
The study of new growths
- Both benign and malignant
What is a neoplasm?
A new growth
What is oncology?
The study and treatment of tumours
What does —oma mean?
Usually a tumour
What are the characteristics of a neoplasm?
- ABNORMAL mass of tissue
- UNCO-ORDINATED growth that exceeds that of normal tissue
- PERSISTS after removal of the stimuli that initiated change
What are the 2 main classes of tumours?
- Benign
- Malignant
Which tissues mainly suffer from tumours?
- Epithelial - lining/covering and glandular
- Connective tissue
- Other tissues - Hemopoietic tissues in bone marrow
What is the growth pattern of benign tumours?
- Grows quite slowly
- Expansion bit like a balloon - all areas will expand at same rate at same time
- Growth remains localised to one area
- Will have fibrous wall surrounding the tissue
What is the histology of benign tumours?
- Resembles tissue of origin
- Uniform cell/nuclear shape and size
- Few dividing cells
What are the clinical effects of benign tumours?
- Lump/pressure/obstruction depending on site and size (may cause swelling)
- +/- hormone secretion
- Treat by local excision (not lethal type of growth but its effect on the patient might be fatal)
What is the growth pattern of malignant tumours?
- Invasion/infiltration
- Metastasis (the transfer from one organ to anther)
- Rapid growth
- No capsule - lacks keeping cells all in one space
What does metastasis mean?
The transfer from one organ to another
What is the histology of malignant tumours?
- Variable resemblance to tissue of origin
- Cellular and nuclear pleomorphism
- Many mitoses, abnormal (number is greatly increased)
What are the clinical effects of malignant tumours?
- Local pressure, infiltration and destruction
- Distant metastasis
- +/- hormone secretion
- Local excision and chemotherapy or radiation if metastases present (depending on the type of tumour and the stage it is at)
What are the effects of benign tumours?
- Palpable lump
- Pressure
- Obstruction
- Function - esp hormone secretion
DEPENDS ON SITE, SIZE AND TUMOUR TYPE
- The effects are not always benign
What is a pleomorphic adenoma?
Benign salivary gland tumour
What is an example of a malignant tumour?
A squamous cell carcinoma
What is the most common epithelium to develop a tumour?
- Squamous epithelium
- Glandular epithelium
What is a papilloma?
A benign tumour derived from epithelium
What is an adenoma?
A benign epithelial tumour in which the cells form recognizable glandular structures or in which the cells are derived from glandular epithelium
What is a carcinoma?
Malignant new growth made up of epithelial cells tending to infiltrate surrounding tissues
What is an adenocarcinoma?
Carcinoma derived from glandular tissue
What is the name for a benign tumour of smooth muscle?
Leiomyoma
What is the name for a benign tumour of fibrous tissue?
Fibroma
What is the name for a benign tumour of bone?
Osteoma
What is the name for a benign tumour of cartilage?
Chondroma
What is the name of a benign tumour of fat?
Lipoma
What is the name of a benign tumour of a blood vessel?
Angioma
What does sarcoma mean?
- This means there is a malignancy of connective tissue
- The word before sarcoma will refer to the type pf connective tissue
What is the name for a malignant tumour of lymphoid tissue?
Lymphoma
What is the name for a malignant haemopoietic tumour?
Leukaemia
What is the name for a benign tumours of melanocytes?
Neavus
What is the name for a malignant tumour of melanocytes?
Melanoma
What is the name for a benign tumour of germ cells?
Benign teratoma
What is the name for a malignant tumour of germ cells?
Malignant teratoma
What are the 2 basic elements needed to cause cancer?
- Genetic basis (change in particular types of genes)
- Environmental stimuli
What are carcinogens?
Environmental factors that cause cancer
What are examples of carcinogens that cause malignant tumours?
- Chemical agents
- Physical agents
- Viruses - oncogenic factors
- May affect tissue directly or may have an indirect effect on other tissues (bladder cancer)
What are examples of chemical carcinogens?
- Tobacco in any form
- Diet, drugs, alcohol
- Alcohol is metabolised/converted to acid aldehyde by the body which is a very dangerous carcinogen
- Asbestos
What is the process of chemical carcinogens causing a tumour?
Two stage:
- Initiation - permanent DNA damage (mutations) (but it remains stable and can stay for many years, however if the person is exposed to another carcinogen, this cell may have an upset genomic stability and therefore be more likely to divide quickly)
- Promotion - agent promotes proliferation, effect may be irreversible (this is the process of another carcinogen acting on the initiated cell)
What is the ‘latent period’ ?
Time from promotion to clinical tumour (takes years)
What is a co-carcinogens?
Carcinogens that need to work together to initiate
What is initiation of carcinogenesis?
When a carcinogen induces a genetic change resulting in a neoplastic potential
What is promotion of carcinogenesis?
Another factor stimulates the initiated cell for division (clonal proliferation). Does not act on non-initiated cells
What is progression of carcinogenesis?
Additional mutations resulting in malignancy
What is clonal expansion?
Growth of cells from original affected cell
What are physical carcinogens?
Ionising radiation
- Damages DNA, causing mutations
- Radioactive metals and gases
- Radium - bone and bone marrow tumours
Which tissues does radiation sensitivity generally affect?
Tissues that are rapidly dividing and rapidly renewed - labile cells
Most to least sensitive tissues to radiation?
- Embryonic tissue
- Haematopoietic organs (spleen, bone marrow)
- Gonads (sex glands)
- Epidermis
- Intestinal mucous membranes (variable)
- Connective tissue
- Muscle tissue and nerve tissue
What are the effects of UV light?
- Damages DNA
- Skin cancer
What are examples of viral carcinogens?
DNA viruses
- more common
- Viral DNA inserted into host DNA
RNA viruses
- Reverse transcribed and then inserted
What is the epidemiology of cancer?
- 20% of deaths
- 2nd most frequent cause of death
- 30% of the population will develop cancer
- Highest in elderly
- Type:
- 90% carcinoma
- 10% lymphoma or sarcoma
What are the causes or oral cancer?
- Tobacco
- Alcohol
- Diet and nutrition
- Oral hygiene
- Viruses
- Immunodeficiency
- Socioeconomic factors
Does sunlight cause oral cancer?
no, sunlight does cause skin cancer and cancer of the lip but not involved in the development of cancer in the oral cavity as sunlight cannot get into the mouth
What are potentially malignant disorders?
Potentially malignant disorders of the oral mucosa are indicators of risk of likely future malignancies occurring in the oral mucosa (whether the mucosa appear normal or if there is a lesion present)
What is Leukoplakia?
White patch that cannot be rubbed off or attributed to any other cause
- Potentially malignant lesion
What is dysplasia?
- Change in the growth and maturation of cells
- Abnormality confined to epithelium, underlying tissue not affected
What are tissues at risk of if they show dysplasia?
Has the potential to become malignant
What is meant by cellular atypia?
Atypical cells
