Introduction to Neoplasia (Part I) Flashcards
What does the term “clonal” mean in terms of neoplasia?
All neoplastic cells are clones of one original altered cell.
Examples of benign tumors
Adenoma
Papilloma
Fibroma
Cystadenofibroma
Examples of malignant tumors
Carcinoma (most common adult type)
Sarcoma
Leukemia
Lymphoma
What are carcinomas?
Malignant neoplasms of epithelial origin, derived from any of the 3 germ layers (ectodermally derived epidermis, mesodermally derived renal tubules, endodermally derived GI tract).
What are sarcomas?
A few examples:
Malignant neoplasms that affect mesenchymal tissues (soft tissues).
Fibrosarcoma, chondrosarcoma, leiomyosarcoma, rhabdomyosarcoma.
What is the parenchyma and stroma?
Parenchyma is the tissue that gives rise to the neoplastic component (the part that is benign or malignant, etc.).
Stroma is the supportive cellular component (structural part) of what the parenchyma resides in. NOT generally neoplastic. Consists of blood vessels and CT.
What is the difference between an adenoma and a polyp?
An adenoma is a benign epithelial neoplasm derived from glands.
A polyp occurs when glandular tissue produces a visible projection from the mucosal surface.
What is a mixed tumor?
A tumor that has several divergent differentiations of a single neoplastic clone. The cells are from the same germ layer.
What is a teratoma?
What is an example?
It is a neoplasm that contains several different cell types from multiple germ cell layers.
An ovarian cystic teratoma may include skin, hair, teeth and glands.
What is tumor differentiation?
The extent to which neoplastic parenchymal cells resemble the corresponding normal cells.
What are the 2 major determinants of tumor differentiation?
- The neoplastic cells’ nuclei and cytoplasm (large nuclei).
- The architectural relationship of the neoplastic cells to the other neoplastic cells and non-neoplastic cells.
Which tumors are well-differentiated?
Poorly-differentiated?
Benign tumors are well-differentiated, meaning they closely resemble the parental cells.
Malignant tumors are poorly differentiated.
The less the differentiation, the more:
Likely the tumor is to be aggressive
What is anaplasia?
Term used to describe the lack of differentiation, which is a hallmark of malignany.
Grading system for neoplasms (4)
Well: closely resembles parental cells.
Moderately: features of parent tissue are identifiable, but is not the dominant pattern, with associated atypia.
Poorly: a small minority of parental cells; associated with anaplasia.
Undifferentiated: tissue of origin cannot be determined. Almost always associated with anaplasia.
Which histopathologic criteria are used w/ anaplasia and what are they? (5)
- Pleomorphism: changes in cell size and shape. All cells within the tumor are not the same size.
- Abnormal nuclear morphology: nuclei are disproportionally large. They are often irregularly shaped and darkly stained.
- Mitoses: indicate rapid cell division. Malignancies are associated w/ atypical, bizarre mitotic figures.
- Loss of polarity: the orientation of anaplastic cells is disturbed. Large masses of cells grow in a disorganized way.
- Ichemic necrosis due to inadequate blood supply from the stroma.
What is dysplasia?
What do dysplastic cells show?
Disordered growth.
May show pleomorphism and abnormal nuclear morphology.
What is the process of dysplastic squamous epithelium?
The epithelium has a normal progression from tall basal cells to flattened apical cells. This process may fail and lead to replacement of the epithelium w/ basal-appearingcells with hyperchromatic nuclei.
There also might be increased amount of mytotic figures.
When does carcinoma in situ occur?
It occurs when dysplastic changes are marked and involve the full thickness of the epithelium, but the lesion does NOT penetrate the basement membrane. It is pre-invasive and may last many years before it becomes invasive.
What 3 things accompany the growth of cancers?
Progressive infiltration
Invasion
Destruction of surrounding tissues
Which tumors can invade?
Malignant only
What is the morphology of a benign tumor?
They produce a fibrous capsule (from fibroblasts and stroma due to hypoxia). The tumor is palpable, non-fixed and easily excised.
What is the morphology of a malignant tumor?
They are poorly demarcated from their surroundings and there is no defined cleavage plane.
What are the 2 most important features that differentiate benign from malignant tumors?
The ability to invade and metastasize
Which malignant cancers don’t tend to metastasize? (2)
Gliomas
Basal cell carcinomas
Which 3 things is the likelihood of metastasis correlated with?
Lack of differentiation, aggressive local invasion and large size.
What are the 3 major pathways for which malignancies are disseminated?
- Direct seeding of body cavities or surface: occurs when a malignant neoplasm penetrates a natural open barrier. Occurs most often into the peritoneal cavity. Common of ovarian carcinomas.
- Lymphatic spread: transport through the lymphatics, which is the most common form of dissemination of carcinomas. Tumors do not have lymphatics, so they take advantage of the host’s.
- Hematogenous spread: most common manner of spreading for sarcomas. Cancer cells generally enter the venous system, which explains why mets to the lung and liver are common.
What is a sentinel lymph node?
The LN where a BX is taken. It is the first node in a regional lymphatic area that receives lymph from the primary tumor.
Which cancers metastasize via hematogenous spread? (3)
Renal cell carcinoma - invades renal v.
Hepatocellular carcinomas - penetrate portal and hepatic radicles.
Mets from the vertebral column - can travel to thyroid and prostate via the paravertebral plexus.
Incidence vs. prevalence
Incidence is the amount of new cases, which prevalence is the amount of people affected total.
What was incidence of cancer in 2008?
How many deaths yearly? Daily?
What is the incidence and mortality expected to be by 2030?
Why?
- 7 mil.
- 6 mil deaths yearly, 21,000 daily.
Incidence of 21.4 mil and mortality of 13.2 mil.
Due to increasing population and age.
Top 4 most common cancers (by incidence) in men in 2014
- Prostate
- Lung
- Colorectal
- Bladder
Top 4 most common cancers (by incidence) in women in 2014
- Breast
- Lung
- Colorectal
- Uterus and thyroid are tied
Which 4 cancers are the highest in mortality rate in men in 2014
- Lung
- Prostate
- Colorectal
- Pancreas
Which 4 cancers are the highest in mortality rate in women in 2014
- Lung
- Breast
- Colorectal
- Pancreas
How many new mutations occur every time a cell divides?
3
What constitutes approximately 95% of neoplasms in the US?
Sporadic malignant neoplasms
Top 4 most common types of lung cancer
Adenocarcinoma (38%)
Squamous cell carcinoma (20%)
Small cell carcinoma (14%)
Large cell carcinoma (3%)
Other (25%)
Parenchyma is generally associated with:
Stroma is generally associated with:
Carcinomas
Sarcomas
Which tumors grow fast? Slow?
Malignant tumors grow fast, benign tumors grow slowly.
