Exam 4: Neoplasia 1 Flashcards
What is neoplasia?
An abnormal mass of tissue with excessive and uncoordinated growth that persists after the original stimulus is absent
What are causes of neoplasia?
Genetic and metabolic cellular changes –> cells fail to respond to normal control
Proliferation –> a microscopic or gross tumor
What is benign neoplasia?
Don’t invade local tissues, still may cause disease
What is malignant neoplasia?
Invade, spread within the body, resulting in death if not under control
What is metastasis?
Spread within the body
What is the preneoplastic change of neoplasia?
Stepwise progression
Change in morphology that indicates abnormal cellular content and thus an increased chance for neoplasia
Dysplasia
Anaplasia
What is dysplasia?
A disorderly pattern of growth
What is anaplasia?
Loss of differentiation
How do you name tumors where the cell of origin is mesenchymal?
Benign: -oma
Malignant: -sarcoma
Describe an epithelial tumor
Can arise from endoderm, mesoderm, and ectoderm
Malignant is a “carcinoma”
Describe an adenoma
Benign, from a gland, or making a tubular pattern
Describe a papilloma
Benign, exophytic/fromdose, from a skin or mucosal surface
Describe a polyp
Benign, smooth, bulging, mucosal surface
What is carcinoma in-situ?
Preinvasive form, neoplasm remains within the epithelium without invasion
What is a squamous carcinoma?
Tumors that demonstrate squamous epithelium
What is a mucinous carcinoma?
Tumors that produce abundant mucin
What is desmoplasia/scirrhous response?
Formation of abundant collagen stroma
What is a mixed tumor?
Multiple cell types in the tumor
What are teratomas?
Started from completely undifferentiated cells, developed from stem cells
Generally occur in areas with reproductive tissue
What is a harmatoma?
Disorganized mature cells in a normal location
What is a choristoma?
Normal mature tissue is an abnormal site
What are tumor characteristics that indicate neoplasia?
Loss of differentiation
Unlimited proliferative potential due to continuous cell division and resistance to cell death
What established the prognosis and determines treatment of tumors?
Tumor grade (degree of differentiation) and stage (extent of spread)
Describe differentiation of a benign tumor
Well differentiated
Structure similar to tissue of origin
No anaplasia
Describe differentiation of a malignant tumor
Poorly differentiated
Tissue of origin may be unclear
Variable anaplasia
Describe growth rate of a benign tumor
Slow, progressive
Rare mitoses
Normal mitoses
Little necrosis
Describe growth rate of a malignant tumor
Rapid growth
Frequent mitoses
Abnormal mitoses
Necrosis
Describe local invasion of a benign tumor
No invasion
Cohesive growth
Capsule often present
Describe local invasion of a malignant tumor
Local invasion
Infiltration
Lacks capsule
Is there metastasis with a benign tumor?
No
Is there metastasis with a malignant tumor?
It is sometimes present
Describe differentiation with neoplasia in general
Neoplastic cells lose the mature differentiated features of cell morphology and organization
In general, malignancies are less differentiated than benign
What does the change in differentiation reflect?
High mitotic rate, chromosomal abnormalitites, and high metabolic activity
What is anisocytosis?
Variation in cell size
What is anisokaryosis?
Variation in nuclear size
What is pleomorphism?
Variation in cell shape
What is hyperchromasia?
Dark nuclei due to increased DNA content
Why do neoplastic cells have a basophilic cytoplasm?
Due to many ribosomes
What is used to identify characteristic features of cells?
Immunohistochemistry
How does proliferation occur?
Neoplastic cells escape the normal limits on cell division, are independent from stimulatory/inhibitory factors, and apoptotic signals
Is tumor growth exponential?
No, there is irreversible cell cycle arrest and cell death occurs within tumors
How do neoplastic cells accumulate more mutations?
Neoplastic cells don’t respond to p53 or other signals
What is the mitotic index of neoplasia?
Average number of tumor cells in a 400x field that have condensed chromosomes and lack a nuclear membrane
What are mechanisms of cell death?
Senescence
Apoptosis
Autphagy
What is senescence?
Damaged cells permanently arrest in G1, a result of p53 or retinoblastoma pathways
How do neoplastic cells prevent sensecence?
They maintain telomerase
How do neoplastic cells remove a pro-apoptotic pathway?
Inactivate p53
What is the latent period of neoplasia transformation?
The time before a tumor is clinically detectable
What is transformation of neoplasia altered by?
Cell death rate, mitotic rate, blood supply, and immune response
What are the stage in the development of tumors?
Initiation
Promotion
Progression
What is initiation?
The introduction of an irreversible genetic change by a carcinogen which may allow a selective advantage in the cell
Genetic and irreversible
What is promotion?
Stimuli (promoters) cause the growth of the initiated cells- a benign tumor
Promoters are non-mutagenic
Nongenetic and reversible
What is progression?
Benign tumors become malignant- a complex and poorly understood process of genetic and epigenetic changes in the tumor cells
Genetic/nongenetic
Irreversible/reversible
What are tumors believed to derive from?
A single cell (clonal)
When is heterogeneity generated?
During tumor development
What does each new mutation in cells lead to?
A subclone of tumor cells
What are subclones selected for?
Increased malignancy
What is in the stroma of tumors?
The connective tissues
What is the stroma of epithelial tumors derived from?
Normal mesenchymal cells
What is the stroma of mesenchymal tumors produced by?
The neoplasm
What are the stromal interactions of tumors?
Complex- exchange of many factors that modulate growth
An extensive fibrous reaction (desmoplasia) is often referred to as a scirrhous response
Describe angiogenesis of neoplasia
Without new vessels, tumor size is limited so the angiogeneic switch allows vessel development
This recruits endothelial cells, migration, and maturation
What are the vessels of a tumor like?
Tortuous
Irregular
Unstable
Leaky
How does the immune system interact with neoplastic cells?
The immune system can detect a variety of antigens expressed by neoplastic cells and destroy them, but as tumors evolve, they figure out ways to get around the immune response
Most tumor cells that are developed are killed off by the immune system
What is a defining characteristic of malignancy?
Metastasis
What does metastasis occur through?
Lymphatics, blood vessels, direct dissemination
This is an inefficient process
Why is metastasis the cause of cancer related mortality?
Interference with critical organ functions
What must a tumor that is trying to metastasize do?
Learn how to cut through the basement membrane and then learn how to move
What is the site of metastasis determined by?
Cell’s ability to interact with endothelial cells and ECM-suitable site for growth
What do mets to local lymph nodes indicate?
Systemic spread
What is lymphatic spread often found with?
Carcinomas
What is hematogenous spread preferred by?
Sarcomas
If the neoplasm reaches the vena cava/heart, where will it metastasize to?
The lungs
If the neoplasm invades the portal vein, where will it metastasize to?
The liver
What do malignant pheochtomocytomas commonly invade?
Vena cava
