Neoplasia Flashcards
What is neoplasia
An abnormal growth of tissue, which exceeds and is uncoordinated
with that of normal tissue and persist in some manner after cessation
of evoked stimulus.
Classification of neoplasia
Neoplasias are classified as benign or malignant.
What 2 components do all tumors have
• The parenchyma:o Determines the biological behavior of the tumor
o From which the tumor derives its name
Stroma of connective tissue and blood vessels.
o Carries the blood supply
o Provides support for the growth of the parenchyma
Describe difference between invasion and metastasis
• Invasion- Infiltration of tumour cells into the surrounding organs.
• Metastasis- the spread of tumour cells to distant organs.
What is anaplasia
Lack of differenciation
Epithelial benign tumors are classified on the basis of
• The cell of origin
• Microscopic pattern
• Macroscopic pattern
What is Adenoma
benign epithelial neoplasms producing gland pattern….OR
… derived from glands but not necessarily exhibiting gland pattern
What is Papilloma
benign epithelial neoplasms growing on any surface that
produce microscopic or macroscopic finger-like pattern
What has the carcinoma suffix
Malignant epithelial tumour
What are mixed tumors and give examples
types of tumours in which more than one line of
differentiation is evident, creating distinct subpopulations of cells.
EXAMPLE:
Pleomorphic adenoma: salivary gland tumour which contains epithelial
components scattered within a myxoid stroma that may contain islands
of cartilage or bone
Tumour Nomenclature Exceptions
Sometimes names persist for historical reasons, such as melanoma of
the skin, or seminoma of the testis, or lymphoma in the lymph nodes,
all of which are malignant and life-threatening (despite ending in –oma
Describe the etiology
- Hereditary- Familial cancers (breast),
- Physical agents- UV radiation , ionizing radiation.
- Chemical carcinogenesis- benzene, asbestos.
- Viruses- HPV(cervical carcinoma) and EBV(burkitts lymphoma).
- Trauma- Chronic leg ulcers (Marjolin’s ulcers).
- Age
o Elderly – most cancers occur between 55-75
o Children – 10% of all kid deaths, leukemia/lymphoma, CNS tumors, sarcoma
6 hall marks of cancer
• Self-sufficiency in growth signals.
Tumours have the capacity to proliferate without external stimuli,
usually as aconsequence of oncogene activation.
• Insensitivity to growth-inhibitory signals.
Tumours may not respond to molecules that inhibit the proliferation of
normal cells, usually because of inactivation of tumour suppressor
genes that encode components of growth inhibitory pathways.
• Evasion of apoptosis.
Tumours are resistant to programmed cell death.
• Limitless replicative potential (immortality).
Tumours have unrestricted proliferative capacity, a stem cell–like
property that permits tumour cells to avoid cellular senescence and
mitotic catastrophe.
Sustained angiogenesis.
Tumour cells, like normal cells, are not able to grow without a vascular supply
( to bring nutrients and oxygen and remove waste products).
o Tumor cells, like all other cells, need blood supply
o Can’t grow more than 1-2cm away from supply vessels
o Tumor cells eventually learn how to stimulate angiogenesis
o Lots of cytokines are involves (VEGF)
o Tumor vessels are abnormal
Normal networks – stable, structure and function of wall and network appropriate to
location
Tumor networks – evolving, unstable, abnormal function inappropriate to location
Ability to invade and metastasize.
Tumour metastases are the cause of the vast majority of cancer deaths
and arise from the interplay of processes that are intrinsic to tumour
cells and signals that are initiated by the tissue environment.
6 differences between benign and malignant tissues
Benign. Malignant
Differentiation Well differentiated. Lack of differentiation
Growth limits. Limited, encapsulated. Unrestricted
Growth rate. Usually progressive andslow Erratic and maybe slow to
rapid
Invasiveness Non-invasive. Invasive and destructive
Metastasis. Absent. Frequently present
Blood supply Adequate Often inadequate leading
to necrosis
Give 3 ways of metastasis
Seeding
o Tumor invades body cavity
o Bits break off at implant on peritoneal cavity
o Ovarian cancer
- Lymphatic drainage
o Tumor spreads to local lymph nodes - Sentinel lymph node (first node to receive lymph drainage) first
o Moves through thoracic duct
o Empties into subclavian vein
o Carcinomas like to spread this way – - Hematogenous spread
o Veins are easier to invade than arteries
o Liver and lungs are most common metastatic destinations
o Some tumors like other sites better
Prostate - bone
Lung cancers - adrenals, brain
o Sarcomas like to spread this way (so do carcinomas)
