neoplasia I

what is a neoplasia? tumor?
neoplasia means “new growth” tumor means swelling (not all tumors are neoplasms)
how are benign tumors named?
cell type + -OMA (ex: adenoma = benign glandular tumor)
how are malignant tumors named?
usually, carcinoma: of an epithelial cell origin (BUT melanoma breaks this rule). sarcoma: of a mesenchymal cell origin, (BUT lymphoma breaks this rule).
what is a leiomyosarcoma?
leiomyo means smooth muscle, so leiomyosarcoma: malignant tumor of the smooth muscle
what is different about adenomas in the colon?
they, aside from everywhere else have the potential to become malignant
how are teratomas named? what do they have inside them?
tera- meaning like “terrible,” “monster-like” and “oma” meaning benign. they are commonly seen in the ovary and could have a tooth, hair, sebaceous material, brain, neuronal elements, thyroid tissue (there could be enough to cause hyperthyroidism)
what does differentiation refer to? what help help determine it? how does it correlate with aggressiveness/prognosis?
differentiation refers to the extent which the tumor resembles the tissue of origin. it is possible to have an adenocarcinoma for example, that so poorly differentiated that its tissue of origin is unknown and generally poorly differentiated tumors have the worst prognosis b/c they are the most aggressive. staining can help determine tissue of origin.
what is anaplasia?
lack of differentiation, very little or poor differentiation – generally assocated with aggressive tumors and poor prognoses
what is pleomorphism?
pleomorphic tumors have cells with a variety of size and shape and are generally poorly differentiated
what is the N/C ratio?
the nuclear/cytoplasmic ratio refers to the size of the nucleus relative to the cytoplasm, many tumors have large nuclei relative to the cytoplasm (due to constant growth and proliferation signals). a prominent nucleolus may be seen with the chromatin inside clumped and disorganized – numerous atypical nuclei w/abnormal chromatin patterns are also signs of malignancy
what are mitotic figures?
cells dividing, malignant tumors are usually dividing rapidly and will have an abundant number of mitotic figures which may be tripolar, tetrapolar (and not bipolar)
what is dysplasia? when is it seen in relation to a malignancy?
dysplasia is disorderly proliferation, many times dysplasia will proceed a malignancy
how do benign tumors appear histologically?
cells are generally organized, they polarity: they are going in the same direction and the cells themselves are relatively uniform with normal n/c ratios
what does the rater of tumor growth generally correlate with?
differentiation; poorly differentiated tumors will generally grow faster
how do benign tumors appear/behave in terms of invasion?
benign tumors may be encapsulated and tend not to invade locally; they are well circumscribed and demarcated
how do malignant tumors appear/behave in terms of invasion?
malignant tumors can penetrate and destroy tissue, with projections that begin to hold onto surrounding tissue
what is the main defining characteristic of malignancy?
the ability to metastasize which is the most lethal aspect of cancer, you can’t keep chasing and removing tumors all over the body
how do benign tumors appear?
they are sharply demarcated from the surrounding tissue and have homogeneous surfaces (malignancies may have areas of necrosis and hemorrhage). histologically they could have a growth limiting capsule
what are the mechanisms of metastasis?
seeding of body cavities, lymphatic spread, and hematogenous spread
how does metastasis via seeding body cavities work?
for example: ovarian tumor gets large and ruptures, it can flood the peritoneum with tumor cells. this happens commonly with ovary, colon and CNS masses
how does metastasis via lymphatic spread work? what tumors are associated with this? what is a caveat for these?
lymphatic spread is typical of carcinomas. example with breast CA: tumor grows in the breast, first place it would spread to would be the ipsilateral axillary lymph nodes (lymph nodes on same side of the breast). it is important to remove the tumor in sx, but also important to know which lymphatics are involved and sometimes remove them (pathologists can determine prognosis/tx by observing lymph node involvement)
how does metastasis via hematogenous spread work? what tumors are associated with this?
hematogenous spread is usually through the blood, and typical of sarcomas; whose sites are often at the liver and lung. sarcomas sometimes have the ability to grow new blood vessels (angiogenesis), and hence are more likely to metastasize via hematogenous routes
how might a malignat tumor appear?
not round and well-shaped, star-shaped/”stellate” appearance, malignant arms/claws that are grabbing the surrounding tissue
where is a common location of metastasis?
the liver, where there are usually numerous metastases at once
what are general characterisitics of benign tumors?
small, although some can be large and benign, well demarcated, well circumscribed, homogenous coloring, slow growing, non invasive, just pushing (pushing margins, does not grab surroundings and invade it, but just push away), well differentiated
what are general characterisitics of malignant tumors?
large, poorly demarcated, rapid growth with hemorrage/necrosis (for a tumor to grow it needs a blood supply/vasculature. so if it is growing too rapidly it may outgrow its blood supply and become necrotic OR it may invade surrounding blood vessels and cause hemorrhage or bleeding). locally invasive, metastatic, poorly differentiated, and pleomorphisms are also seen
what are factors in cancer formation?
environment (including nutrition/diet and smoking), age (DNA repair genes, tumor suppressor genes do not work quite as well), and heredity
what are palpable characteristics of malignant tumors?
hard, irregular outline, poorly moble, fixed, usually painless, rapid growth, and systemic signs
what are palpable characteristics of benign tumors?
soft, smooth outlines, freely moble, not fixed, +/- pain, slow growth, no systemic signs
what are some different types of tumors?
well circumscribed, obscured, micro-lobuled, ill-defined, and speculated
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