Path Book: Chapter 5 Neoplasia pg 162-172 Flashcards
Cancer is a genetic disorder. Are these genetic alterations heritable?
As a result, cells harboring these alterations are subject to darwinian selection (survival of the fittest, arguably the most important scientific concept yet conceived), with cells bearing mutations that provide them with growth or survival advantages outcompeting their neighbors and thus coming to dominate the population.
Accumulation of mutations gives rise to a set of properties that have been called ______.
hallmarks of cancer.
What are some hallmarks of cancer?
These include:
(1) self-sufficiency in growth signals whereby the growth of cancers becomes autonomous and is unregulated by physiologic cues
(2) lack of response to growth inhibitory signals that control non-neoplastic cellularproliferations such as hyperplasias;
(3) evasion of cell death, allowing cancer cells to survive under conditions that induce apoptosis in normal cells;
(4) limitless replicative potential, thus making cancer cells immortal;
(5) development of angiogenesis to sustain the growth of cancer cells;
(6) ability to invade local tissues and spread to distant sites;
(7) reprogramming of metabolic pathways—specifically, a switch to aerobic glycolysis even when there is abundant oxygen; and
(8) ability to evade the immune system. The genetic alterations that give rise to these hallmarks of cancers are sustained and enabled by the development of genomic instability, adding fuel to the fire. The molecular underpinnings of these hallmarks are discussed in detail in a later section.
Neoplasia literally means what?
new growth. Neoplastic cells are said to be transformed because they continue to repli-cate, apparently oblivious to the regulatory influences that control normal cell growth.
What does the term malignant mean?
Malignant, as applied to a neoplasm, implies that the lesion can invade and destroy adjacent structures and spread to distant sites (metastasize) to cause death.
All tumors, benign and malignant, have two basic components:
(1) the parenchyma, made up of transformed or neoplastic cells, and
(2) the supporting, host-derived, non-neoplastic stroma, made up of connective tissue, blood vessels, and host-derived inflammatory cells.
The stroma is crucial to the growth of the neoplasm, since it carries the blood supply and provides support for the growth of parenchymal cells.
In general, benign tumors are designated by attaching the suffix “-oma” to the cell type from which the tumor arises.
E.g. A benign tumor arising in fibrous tissue is a fibroma; a benign cartilaginous tumor is a chondroma.
The nomenclature of benign epithelial tumors is more complex. Explain.
They are classified sometimes on the basis of their microscopic pattern and sometimes on the basis of their macroscopic pattern. Others are classified by their cells of origin.
What is an adenoma?
generally applied to benign epithelial neoplasms producing gland patterns and to neoplasms derived from glands but not necessarily exhibiting glandular patterns.
A benign epithelial neo- plasm arising from renal tubule cells and growing in glandlike patterns is termed an adenoma, as is a mass of benign epithelial cells that produces no glandular patterns but has its origin in the adrenal cortex.
What are papillomas?
Papillomas are benign epithelial neoplasms, growing on any surface, that produce microscopic or macroscopic finger-like fronds.
What is a polyp?
A polyp is a mass that projects above a mucosal surface, as in the gut, to form a macroscopically visible structure.
Although this term commonly is used for benign tumors, some malignant tumors also may grow as polyps, whereas other polyps (such as nasal polyps) are not neoplastic but inflammatory in origin.
What are Cystadenomas?
Cystadenomas are hollow cystic masses that typically arise in the ovary. Benign in nature.
Malignant neoplasms arising in “solid” mesenchymal tissues or its derivatives are called ____.
sarcomas.
Sarcomas are designated by the cell type of which they are composed, which is presumably their cell of origin. Thus, a cancer of fibrous tissue origin is a fibrosarcoma, and a malignant neoplasm composed of chondrocytes is a chondrosarcoma.
Neoplasms arising from the mesenchymal cells of the blood are called ____.
leukemias or lymphomas.
While the epithelia of the body are derived from all three germ cell layers, malignant neoplasms of epithelial cells are called ____ regardless of the tissue of origin.
carcinomas. Thus, a malignant neoplasm arising in the renal tubular epithelium (mesoderm) is a carcinoma, as are the cancers arising in the skin (ectoderm) and lining epithelium of the gut (endoderm).
Furthermore, mesoderm may give rise to carcinomas (epithelial), sarcomas (mesenchymal), and hematolymphoid tumors (leukemias and lymphomas).
Carcinomas are subdivided further. How?
1) Carcinomas that grow in a glandular pattern are called adenocarcinoma
2) Those that produce squamous cells are called squamous cell carcinomas.
Sometimes the tissue or organ of origin can be identified, as in the designation of renal cell adenocarcinoma. Sometimes the tumor shows little or no differentiation and must be called poorly differenti- ated or undifferentiated carcinoma.
T or F. The transformed cells in a neoplasm, whether benign or malignant, often resemble each other.
T. as though all had been derived from a single progenitor, consistent with the monoclonal origin of tumors.
What are mixed tumors?
In some unusual instances, however, the tumor cells undergo divergent differentiation, creating so-called mixed tumors.
What is a common example of a mixed tumor?
1) The best example is mixed tumor of salivary gland. These tumors have obvious epi- thelial components dispersed throughout a fibromyxoid stroma, sometimes harboring islands of cartilage or bone.
All of these diverse elements are thought to derive from epithelial cells or myoepithelial cells, or both, and the preferred designation for these neoplasms is pleo- morphic adenoma.
What’s another type of mixed tumor?
Fibroadenoma of the female breast.
This benign tumor contains a mixture of proliferating ductal elements (adenoma) embedded in a loose fibrous tissue (fibroma).
Although only the fibrous component is neoplastic, the term fibroadenoma remains in common usage.
What is a teratoma?
Teratoma is a special type of mixed tumor that contains recognizable mature or immature cells or tissues representative of more than one germ cell layer and sometimes all three.
What do teratomas originate from?
totipotential germ cells such as those normally present in the ovary and testis and sometimes abnormally present in sequestered midline embryonic rests. Germ cells have the capacity to differenti- ate into any of the cell types found in the adult body; not surprisingly, therefore, they may give rise to neoplasms that mimic, in helter-skelter fashion, bits of bone, epithelium, muscle, fat, nerve, and other tissues.
What are some ‘omas’ that are malignant neoplasms?
lymphoma, mesothelioma, melanoma, and seminoma
What is a Hamartoma?
A mass of disorganized tissue indigenous to the particular site. Histopathologic examination may show a mass of mature but disorganized hepatic cells, blood vessels, and possibly bile ducts within the liver, or a nodule in the lung containing islands of cartilage, bronchi, and blood vessels.
Hamartomas have traditionally been considered developmental malformations, but some genetic studies have shown the presence of acquired translocations, suggesting a neoplastic origin.
What is a choristoma?
a congenital anomaly consisting of a het- erotopic rest of cells. For example, a small nodule of well-developed and normally organized pancreatic tissue may be found in the submucosa of the stomach, duodenum, or small intestine. This heterotopic rest may be replete with islets of Langerhans and exocrine glands. The designation -oma, connoting a neoplasm, imparts to the heterotopic rest a gravity far beyond its usual trivial significance.
What is a benign blood vessel neoplasm called?
hemangioma
What is a malignant blood vessel neoplasm called?
angiosarcoma
What is a benign lymph vessel neoplasm called?
lymphangioma
What is a malignant neoplasm of smooth muscle called? benign?
benign- leiomyoma
malignant- leiomyosacroma
What is a malignant neoplasm of striated muscle called? benign?
benign- rhabdomyoma
malignant-rhabdomyosarcoma
T or F. In general, benign tumors appear to be genetically “simple,” harboring fewer muta- tions than cancers, and genetically stable, changing little in genotype over time.
T. Thus, they transform to malignancies infrequently.
There are four fundamental features by which benign and malignant tumors can be distinguished:
1) differentiation and anaplasia,
2) rate of growth,
3) local invasion, and
4) metastasis.
Differentiation and anaplasia are characteristics seen only in the _____ that constitute the transformed elements of neoplasms.
parenchymal cells. The differentiation of parenchymal tumor cells refers to the extent to which they resemble their normal forebears morphologically and functionally.
Describe the differentiation of benign neoplasms.
Benign neoplasms are composed of well-differentiated cells that closely resemble their normal counterparts. In well-differentiated benign tumors, mitoses are usually rare and are of normal configuration.
