10_Neoplasia II Flashcards
neoplasm:
define
- abnormal mass of tissue which exceeds and is uncoordinated w/ that of the normal tissues;
- persists in the same excessive manner after the cessation of the stimuli which evoked the change
what are the 3 basic principles of neoplasia?
- New tissue growth
- Unregulated, irreversible, and monoclonal
- Differs from hyperplasia and tissue repair
what are the 6 different types of abnormal cell growth?
- atrophy
- hyperplasia
- dysplasia
- metaplasia
- hypertrophy
- hypertrophy AND hyperplasia
hypertrophy:
define
- an increase in cell size; can be physiologic or pathologic
- e.g.
- Increase in skeletal muscle fiber size is a physiologic response to exercise, but
- cardiac hypertrophy shown above is a pathologic response to abnormally elevated blood pressure.
hyperplasia:
define
- an increase in the number of cells.
- e.g.
- Postpartum breast lobules undergo hyperplasia for lactation, but
- endometrial hyperplasia in a postmenopausal woman is abnormal
The large fronds of endometrium seen in this uterus opened to reveal the endometrial cavity are a result of hyperplasia. This resulted from increased estrogen. With hyperplasia, there is an increase in cell numbers to produce an increase in tissue size. However, the cells are normal in appearance. Sometimes hyperplasias can be “atypical” and the cells not completely normal. Such conditions can be premalignant.
metaplasia:
define
- an initial change from normal cells to a different cell type
- e.g. (such as chronic irritation of cigarette smoke causing ciliated pseudostratified epithelium to be replaced by squamous epithelium more able to withstand the insult)
dysplasia:
define
- an increasing degree of disordered growth or maturation of the tissue (often thought to precede neoplasia)
- e.g.
- such as cervical dysplasia as a result of human papillomavirus infection. Dysplasia is still a reversible process.
- However, once the transformation to neoplasia has been made, the process is not reversible.
relationship of neoplasia, dysplasia, and metaplasia?
there is a natural history from metaplasia to dysplasia to neoplasia.
e.g.This is best evidenced in development of uterine cervix and respiratory tract neoplasms
neoplasia:
define, and examples
- “New growth” ; Unregulated cell proliferation as a result of genetic changes.
- ex:
- In adenocarcinoma of the lung, autonomous growth of glandular cells occurs as a result of oncogene expression (KRAS) and loss of tumour suppressor genes (p53).
anaplasia:
define, and examples
- “To form backward” ; Lack of cell differentiation; a hallmark of malignancy
- e.g. In colorectal cancer, there is progressive dedifferentiation of colon epithelial cell. High grade anaplastic cells are hyperchromatic, pleomorphic, and disorganized.
what is the mechanism and cancer risk for:
hypertrophy
- Mech: Increase in protein production in response to mechanical stress and growth factors
- Cancer risk: negative
what is the mechanism and cancer risk for:
hyperplasia
- mech: Growth factors stimulate cell proliferation from existing mature cells or stem cells.
- cancer risk: +
what is the mechanism and cancer risk for:
metaplasia
- mech:
- External stimuli triggers altered gene transcription,
- leading to differentiation of stem cells to a different cell type;
- not a conversion from one differentiated cell type to another.
- cancer risk: ++
what is the mechanism and cancer risk:
dysplasia
- mech: Dysregulation of cell maturation and growth as a result of altered gene expression or genetic mutations.
- cancer risk: +++
what is the mechanism and cancer risk of:
anaplasia
- mech: New theories suggest that anaplasia results from lack of differentiation of cancer stem cells instead of dedifferentiation of mature cells.
- cancer risk: cancer formed
what is the mechanism and cancer risk of:
neoplasia
- mech: Genetic and epigenetic changes
- cancer risk: cancer formed