Neoplasia Flashcards
occurs when a group of cells becomes free of normal growth control mechanisms, grows without regard for the normal structural and functional aspects of a tissue or an organ and excessive growth becomes autonomous
neoplasia
neoplasia literally means?
new growth
called as tissue growth
neoplasm
an abnormal mass of tissue, the growth of which exceeds and is uncoordinated with that of normal tissues, and persist in the same excessive manner after cessation
of the stimulusthat evoked the
change.
neoplasm
three important features of neoplasm;
• it is an excessive tissue growth
• it lacks responsiveness to
control mechanisms
• it lacks continued dependence
on the stimulus that initiated it
abnormal mass of tissue due to an increase in the number of constituent cells
hyperplasia
retrogressive change that is reversible and is responsive to growth control
mechanisms
hyperplasia
is a form of pathological hyperplasia
neoplasia
where thought to be a malady of a
mysterious cause
neoplasm
the external appearance of which seemed to be being eaten away by small crabs. This observation led to the naming of the condition as?
cancer
the term cancer has been associated with?
malignant neoplasm
is a tissue swelling or mass that may or may not be neoplasm
tumor
Common usage of the word tumor, however, comes to mean?
neoplasm
is the study of neoplasia
oncology
this word oncology is the basis of?
oncogenesis and oncogenic
relate to the induction of neoplasia
oncogenesis and oncogenic
Information on cell growth control
mechanisms was derived from?
cell culture
When normal cells are grown
in vitro, they spread out to form a
single sheet of cells which called?
cell monolayer
Growth ceases when the cells reach a
certain population density where they remain quiescent but healthy. This
mechanism is called?
density-dependent inhibition or contact inhibition for growth
governed by chemical messengers
chalones
grow in haphazard fashion, piling up into multiple layers,and tend to grow
until they have exhausted the culture media, with less responsiveness to density dependent inhibition.
neoplastic cells
When normal cells, as influenced by some factors, loses their innate characteristics and become neoplastic cells, the process is known as?
neoplastic transformation
Morphologically, transformed cells
exhibit the following characteristics:
1) May or may not resemble their
cell origin
2) Presents increased nucleus to
cytoplasmic ratio, the nuclei being
enlarged, hyperchromatic and may be multinucleated
3) Chromosomes may present mitotic figures
4) They lack orientation to adjacent cells;
5) Decreased rough endoplasmic
reticulum and increased free
ribosomes.
Besides morphological changes,
transformed cells exhibit the
following characteristics:
✓ transplant ability
✓ immortality
✓ tumorigenicity
✓ antigenic changes
✓ karyotypic changes
✓ biochemical changes
will grow in tissue culture or in syngeneic host
transplantability
will divide and replicate indefinitely provided that nutrients required for growth are present
immortality
forms tumors or tissue masses in syngeneic host
tumorigenicity
presents altered surface antigens
antigenic changes
although the observed karyotypic
changes arerarely characteristic of
any one tumor, chromosomal damage or alterationin base pairs may be basic to the induction of neoplasm
karyotypic changes
neoplastic cells contains;
✓ less cyclic adenosine monophosphate (cAMP)
✓ more cyclic guanosine
monophosphate (cGMP)
Based on the tissue origin, the
neoplasm could be?
epithelial or mesenchymal
derived from one embryonic germ
layer
mixed neoplasm
example of mixed neoplasm
mammary gland tumors in dogs
a neoplasm containing tissue derived
from more than one germ layer, and
may contain any number of tissues of
any type, including bone, skin, nervous tissue, muscle, hair and others.
teratoma
describes those that are relatively
inoffensive, grow slowly by expansion, are circumscribed, does not undergo
metastasis
benign neoplasm
refers to those that are aggressive and potentially life threatening.
malignant neoplasm
benign neoplasm derived from fibroblast
fibroma
Benign neoplasms derived from
glandular epithelia
adenomas
“adenoma” is nonspecific, the tissue origin is usually named;
✓ adenoma of sweat gland
✓ thyroid gland adenoma
✓ adrenal cortex adenoma
it forms cystic cavitations
cystadenoma
is one that forms branching finger-like projections into the lumen
papillary adenoma
one derived from ducts
ductural adenoma
arenneoplasms growing at the surfaces
polyps or papilloma
Malignant neoplasms of mesenchymal origin
sarcoma
Malignant neoplasms of epithelial origin
carcinoma
form solid patters, and thosethat form recognizable ducts; tubules or acini
adenocarcinoma
example of adenocarcinoma
✓ squamous cell carcinoma
✓ adenocarcinoma of sweat glands
neoplasms fail to mimic their tissue origin sufficiently for them to be recognized
poorly differentiated sarcoma or carcinoma
refers to the degree by which they
resemblemorphologically and
functionally the tissues from which
they originate
neoplastic cell differentiation
are usually well differentiated such that they resemble the tissue oforigin both cytologically and architecturally
benign neoplasm
vary greatly in the degree of differentiation, and they usually exhibit anaplasia
malignant neoplasm
the failure of cells to differentiate pr loss differentiation
anaplasia
is one of the hallmark’s and the most important morphologic feature of malignancy
anaplasia
anaplastic cells usually exhibit __________ where their nuclei become large, hyperchromatic or vesicular
pleomorphism
retain the functional characteristics of the parent tissue, such that even their functional activity is intact
well-differentiated neoplasms
Functional activity is in fact one of the basis on which the origin of neoplasms may be know;
✓ melanomas produce melanin
✓ osteosarcomas produce osteoid
✓ adenocarcinoma of thyroid produce colloid
grow at a rapid rate than normal germinal cells, and may imply that neoplastic cells divide at a more rapid rate than normal tissue, which is not the case
malignant neoplasm
what determines the growth rate of tissue?
✓ length of the mitotic cycle
✓ growth fraction
✓ rate of cell loss through necrosis and apoptosis
in many cells, full differentiation precludes further ________
mitotic division
contains a high proportion of cells unable to divide and so grow slowly
benign neoplasm
contain many cells in the growth fraction and usually grows at a more rapid rate.
malignant neoplasm
