Transcript TUMORS and NEOPLASM

TUMORS and NEOPLASM
Neoplasia and Neoplasm
Neoplasm is an abnormal mass of tissue as
a result of neoplasia
Neoplasia (new growth in Greek) is the
abnormal proliferation of cells.
Definitions
• Neoplasm is mass of tissue that grows
excessively, and keeps growing even if you
remove the stimulus that started it off!
• Tumor = neoplasm
• Types: Benign tumor and Malignant tumor
Cancer = Latin for “crab”
Definitions
Benign Tumors
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Small
Slow-growing
Non-invasive
Well-differentiated
Stay localized
• Stay where they are.
• Can’t invade or
metastasize.
Malignant Tumors
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Large
Fast-growing
Invasive
Poorly-differentiated
Metastasize
• Infiltrate, invade, destroy
surrounding tissue.
• Then metastasize to other
parts of body.
Benign versus Malignant
Benign Tumors
• Usually designated by adding “-oma” to cell type
• Adenoma – benign tumor arising from glandular
cells
• Leiomyoma – benign tumor arising from smooth
muscle cells
• Chondroma – benign tumor arising from
chondrocytes
• Other benign tumor names
• Papilloma – has finger-like projections
• Polyp – projects upward, forming a lump
• Cystadenoma – has hollow spaces (cysts) inside
Benign Tumors
Thyroid adenoma
Oral papilloma
Thyroid adenoma
Colon polyp
Normal thyroid
Ovarian cystadenoma
Malignant Tumors
• Carcinomas – arise in epithelial tissue
• Adenocarcinoma – malignant tumor of glandular cells
• Squamous cell carcinoma – malignant tumor of
squamous cells
• Sarcomas – arise in mesenchymal tissue
• Chondrosarcoma – malignant tumor of chondrocytes
• Angiosarcoma – malignant tumor of blood vessels
• Rhabdomyosarcoma – malignant tumor of skeletal
muscle cells
Mesenchymal tissue are capable of developing into connective tissue, bone, cartilage,
the lymphatic system, and the circulatory system
Malignant Tumors
Neoplasm
Benign
Adenoma
Angioma
Rhabdomyoma
Malignant
Carcinoma
Squamous cell carcinoma
Adenocarcinoma
Sarcoma
Angiosarcoma
Rhabdomyosarcoma
Tumor Characteristics
Differentiation and Anaplasia
• Differentiation is how much the tumor cells resemble
their cells of origin.
• well-differentiated – closely resembles
• moderately-differentiated – sort of resembles
• poorly-differentiated – doesn’t resemble
• Benign tumors are usually well-differentiated
• Malignant tumors can’t show any level of differentiation.
Differentiation and Anaplasia
Anaplasia refers to a reversion of differentiation in cells
• Literally, “to form (-plasia) backwards (ana-)”
• Just means cells are very poorly-differentiated
• Almost always indicates malignancy
Anaplastic cells show:
• Pleomorphism occurrence of two or more structural forms in
the size and shape of cells and/or their nuclei
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Hyperchromatic, large nuclei
Unusual nuclear shapes, distinct nucleoli
Lots of mitoses, and atypical mitoses
Architectural disorder
Mitosis divides the chromosomes in a cell nucleus.
Anaplastic carcinoma
Differentiation and Anaplasia
Dysplasia = disorderly (dys-) growth (-plasia)
• “Dysplasia” is used to describe disorderly changes
in non-neoplastic epithelial cells.
• Graded as mild, moderate or severe.
• Mild-moderate: usually reversible
• Severe: usually progresses to carcinoma in situ (CIS).
• Next step after CIS: invasive carcinoma.
Dysplastic cells show:
• Pleomorphism
• Architectural disorder
• Lots of mitoses
• Hyperchromatic, large
nuclei
Q. Wait a minute, “dysplasia” sounds suspiciously
similar to “differentiation” – what’s the difference?
A. Both terms describe whether cells look normal or not!
But:
• “differentiation” is only used with neoplastic cells, and
“dysplasia” is only used with non-neoplastic cells!
• “dysplasia” is only used with epithelial cells, but
“differentiation” can apply to any cell type.
Non-neoplastic epithelial cells
carcinoma
in situ
mild
dysplasia
moderate
dysplasia
severe
dysplasia
Neoplastic cells
welldifferentiated
moderatelydifferentiated
poorlydifferentiated
anaplastic
Rate of Growth
Generalizations
• Malignant tumors grow faster than benign ones.
• Poorly-differentiated tumors grow faster than welldifferentiated ones.
• Growth is dependent on:
• Blood supply
• Hormonal factors
• Emergence of aggressive sub-clones ‫استنساخ‬
Carcinoma in situ
Invasive carcinoma
Invasive carcinoma
Metastasizing carcinoma
Liver with multiple metastases
Metastasis
• Metastasis is development of secondary tumor in
distant tissues
• Half of all patients with malignancies have meets at
the time of diagnosis!!
• Metastasis depends on:
• Type of tumor
• Size of tumor
• Degree of differentiation of tumor
Metastasis
Three ways tumors metastasize
• Seeding
• Lymphatic spread
• Hematogenous spread
Metastasis
Three ways tumors metastasize
1. Seeding
• Tumor invades body cavity
• Bits break off and implant on peritoneal surfaces
• Ovarian cancer
2. Lymphatic spread
• Tumor spreads to local lymph nodes
The sentinel lymph node is
• Sentinel lymph node first
the hypothetical first lymph
node or group of nodes
reached by metastasizing
• Moves through thoracic duct
cancer cells from a primary
tumor.
• Empties into subclavian vein
• Carcinomas like to spread this way
Overview of the Lymph Nodes, Trunks
Lymphatic System
Right
lymphatic
duct
Right
subclavian
vein
Lymph capillaries converge to
become collecting vessels and
end up as either
Thoracic duct or right
lymphatic duct
Cysterna Chyli
Left subclavian vein
Thoracic (left lymphatic)
duct
Metastasis
Three ways tumors metastasize
3. Hematogenous spread
• Veins are easier to invade than arteries
• Liver and lungs are most common metastatic
destinations
• Sarcomas like to spread this way (but so do
carcinomas)
Liver seeded with metastatic ovarian carcinoma
Lymphatic spread
Hematogenous spread
Cancer Incidence
• 1.4 million new cases of cancer last year
• 565,000 deaths from cancer last year
• Cancer is 2nd leading cause of death (after heart
disease)
• Most common cancers
• Men: Prostate
• Women: Breast
• Deadliest cancers
• Men: Lung
• Women: Lung
Cancer Incidence
Death rates have changed over past 3 years
• Decrease in death rates for:
• Cervical cancer (pap smears)
• Colon cancer (earlier detection)
• Breast cancer (earlier detection)
• Lung cancer in men (less smokers)
• Some types of leukemia (new treatment)
• Increase in death rates for:
• Lung cancer in women (more smokers)
Cause of cancer
• Basic underlying cause of cancer: Non-lethal genetic damage
• Four kinds of normal genes are damaged:
• Genes that promote growth (“proto-oncogenes”)
• Genes that inhibit growth (“tumor-suppressor
genes”)
• Genes that regulate apoptosis
• Genes involved in DNA repair
• Cancers develop in multiple steps
Cancer Genes
“Cancer genes” cause bad things in cells:
• Autonomous growth
• Insensitivity to growth-inhibitory signals
• Evasion of apoptosis
• Limitless replication
• Sustained angiogenesis
• Invasion (infiltration/penetration) and metastasis
Definitions
• Proto-oncogene: a normal gene whose product
promotes cell growth.
• Oncogene: mutated proto-oncogene!
to grow autonomously!
Causes cell
• Oncoprotein: the product of an oncogene.
Carcinogenic Agents
1. Chemicals
2. Radiation
3. Bugs/viruses
Carcinogenic Agents
1- Chemicals
• Direct-acting agents
• Indirect-acting agents
• Require conversion to become carcinogenic
• Examples:
• hydrocarbons (in tobacco, charred meats)
• aflatoxin B (from Aspergillus-infected grains, nuts)
• nitrites (food preservative)
Carcinogenic Agents
2- Radiation
• Ionizing radiation
• Causes chromosome breakage, translocations
• Examples:
• Unprotected miners: lung cancer
• Atomic bomb survivors: leukemia, other cancers
• Therapeutic head/neck radiation: thyroid cancer
Chromosome translocation is a chromosome abnormality caused
by rearrangement of parts between nonhomologous chromosomes. A
gene fusion may be created when the translocation joins two
otherwise separated genes, the occurrence of which is common in
cancer.
Carcinogenic Agents
3- Bugs
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HTLV-1: T-cell lymphoma
Human papilloma virus: Cervical cancer
Epstein Bar virus: various lymphomas
Hepatitis B and C: hepatocellular carcinoma
H. pylori: gastric cancer, lymphoma
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Define neoplasm and neoplasia?
Write the difference between benign and malignant tumor?
Give 5 examples of benign tumor and the organs they affect?
Write the types of malignant tumors with example based on
their origin?
Define anaplasia?
Write the characteristics of anaplastic cells?
Define dysplasia?
Write the difference between differentiation and dysplasia?
Define metastasis? Write the factors on which metastasis
depends on?
Explain the 3 ways in which the tumors metastasize?
What are the 4 kinds of genes that are damaged in cancer?
Write the characteristics of cancer genes?
Explain different carcinogenic agents responsible for causing
cancer?