Pathology Key Terms for Medical Students

What is homeostasis?

• a state of balance among all the body systems needed for the body to survive and function correctly (state of equilibrium within the body)

What is anaplasia?

• pathologic description of cells, describing a loss of differentiation and more primitive appearance

What is sarcoma and how does it spread?

• tumors arising from mesenchymal cells, connective tissue, or nervous tissue - tend to spread via blood

What is carcinoma and how does it spread?

• tumors that originate from the epithelium and include all tissues that cover a surface or line a cavity - tend to spread via lymph

What is apoptosis?

• (normal) programmed cell death

What is carcinogen?

• a substance capable of causing cancer in living tissue

For Solid tissue (incisional/excisional biopsy) specimen, how are they examined during a microscopic exam? (3)

• Tissue is fixed (preserves structures in tissue)

• hardened with paraffin wax and sliced with a microtome machine

• stained

How are FNA, core needle, or exfoliative cytology biopsy specimen, how are they examined during a microscopic exam?

• Cells are smeared thinly on slides first, then fixed & stained

What is the TNM staging system?

• system that evaluations the extent of the tumor at the time of diagnosis

  • T: tumor size and degree of invasiveness (given a number of 1-4)

  • N - regional node involvement (0-3)

  • M - presence or absence of distant metastasis (0 or 1)

What is adenocarcinoma?

• epithelial cells that are glandular; an example is tissue lining the stomach: a tumor originating in the cells of this lining is called adenocarcinoma of the stomach

What is liposarcoma?

• soft tissue sarcoma (STS) arising from fat

What is hypoxia?

• oxygen deprivation; no O2 = the cell cannot manufacture energy needed to sustain life = cell death

What is pleomorphism?

• cells that grow in multiple shapes and sizes

What is neoplasm and at level does it occur at?

• new growth: an abnormal mass of tissue that results from uncontrolled new cell growth.

• occurs at the molecular level (mutated DNA)

What is squamous cell carcinoma?

• cancer originating in epithelial tissue from cells that are squamous (single or multiple layers) in size and shape; examples include lung and skin cancer

What is lymphoma?

• cancer of the lymph system (lymphocytes)

What is pathology?

• science that studies changes in bodily structure and function as a result of disease

What is FNA (fine needle aspiration) biopsy?

• The removal of tissue or fluid with a thin needle for biopsy

What is core needle biopsy and what does it allow?

• larger gauge needle; allows for greater tissue sample

What is excisional biopsy?

• removal of the entire tumor + margin so a diagnosis can be made

What is incisional biopsy?

• removal of part of the tumor so a diagnosis can be made

What is leukemia?

• cancer that arises in the blood (bone marrow and other blood-forming organs produce increased numbers of immature or abnormal leukocytes)

What is inflammation?

• inflammation - the body’s response to an injury or an infection

What is carcinogenesis?

• the initiation of cancer formation

What is carcinoma in situ?

• cellular changes in epithelial tissues that do not extend beyond the basement membrane ("in situ" means original place, so these abnormal cells have not spread); considered stage 0

Failure to maintain homeostasis results in what 4 things?

• Cellular injury

• Changes in cellular structure that are recognizable

• Tissue damage

• Disease

What 2 cellular changes occur when homeostasis is NOT maintained?

• Reversible: the cell repairs and survives the injury

• irreversible: apoptosis OR necrosis

How does irreversible injury/damage show up under the microscope?

• appear as a series of color alterations compared to typical staining patterns and irregularities in the structure of the cell’s nucleus

Cellular changes occur in both _____and_____ cells & initiate an inflammatory response

• normal & malignant cells

What is an inflammatory response?

• complex immunochemical reaction that takes place when cells have become injured/damaged

What is an acute response to inflammation?

• body’s response to sudden damage (evolves in a few hours)

What is a chronic response to inflammation?

• The body continues to have an inflammatory response for longer periods of time, even without the presence of injury/damage (associated with chronic disease)

What six things sparks an inflammatory response?

1. hypoxia: e.g superior vena cava symptom, heart attack

2. microbial (bacterial response)- most common

3. allergic/immune reactions

4. chemicals: e.g chemo

5. ionizing radiation

6. tumor or cancer

What are the 4 cardinal features of an inflammatory response?

1. redness

2. warmth

3. swelling

4. pain

3 steps in the inflammatory process

1. After damage, cells release histamines (cells that cause vasodilation and vascular permeability)

2. Swelling pushes on sensitive nerve endings = pain

3. Leaked interstitial fluid is made up of WBCs, called phagocytes (ingest damaged cells or pathogens), and platelets (clot blood/seal wounds)

What is vasodilation and vascular permeability?

• vasodilation: increased blood flow resulting in increased intravascular pressure (warmth/redness)

• vascular permeability: increases the escape of fluid from blood vessels into the surrounding tissue (swelling)

TRUE /FALSE: neoplasia can be benign or malignant

• TRUE

  • benign: non threatening (ends in -oma)

  • malignant: threatening (ends in sarcoma or carcinoma)

Cancer is divided in what 4 categories and the definitions?

1. carcinoma: malignant tumor arising from epithelial cells; lymphatic spread; mets in lymph nodes are common

2. Sarcoma: malignant tumor arising from connective tissue/ nervous system; blood spread

3. leukemia: malignancy of blood/bone marrow

4. Lymphoma: malignancy of the lymph system

What are the 3 links for cancer formation (carcinogenesis)?

NO absolute cause, but definite links include:

• viral: In humans, no specific viruses have been proven to cause cancer alone; however, there are strong associations between some viruses and cancer formation

• chemical: pesticides, tobacco, asbestos, alkylating chemotherapy agents

• radiation:  ionizing radiation; e.g., UV rays (sunlight/tanning beds), x-rays, gamma rays

What 4 viruses are associated with the formation of cancer (carcinogenesis)? list viruses and cancers they cause

1. Human Papillomavirus (HPV): cervix and H&N

2. Epstein-Barr Virus (EBV): nasopharynx and lymphoma

3. Hepatitis B virus (HBV): liver cancer

4. Human T-cell leukemia type I virus (HTLV-1)

TRUE/ FALSE: Radiation carcinogenesis may cause primary or radiation induced secondary malignancy

• TRUE

What are the 4 contributing factors to the development of secondary cancers with radiation?

• total dose of radiation received,

• volume irradiated

• type of tissue irradiated

• If chemo was also given

Higher risk factors for secondary cancer development with radiation?

• patients who received initial radiation treatment at a young age

• those who smoke

What are the most common radiation-induced secondary malignancies?

• sarcomas (osteosarcoma & soft tissue sarcomas)

Proto-oncogenes & tumor suppressor genes (anti-oncogenes) are part of the ______human genome.

• normal

What are  Proto-oncogenes (the “gas pedal”)? (2)

• normal genes that help cells grow

• When mutated, they become permanently turned on (activated inappropriately) and cause cancer & are now called oncogenes

What are Oncogenes (the “stuck gas pedal”)?

• mutated (abnormal) proto-oncogenes that lead to cancer

What are Tumor suppressor genes (the “brakes”)? (2)

• normal genes that slow down/stop cell division, repair DNA damage within the cell, or tell the cell to die (apoptosis)

• Inactivation of these genes leads to cancer

When do Genetic mutations occur? (4)

• Genetically (inherited)

• Due to aging

• After exposure to carcinogens (sun, radiation, cigarette smoke, etc.)

• Randomly

4  Types of mutations

• Gene amplification – over-production/over-expression of genes

• Gene transposition – movement of genes from one site to another on a chromosome

• Chromosome translocations – chromosomal breaks that attach to another chromosome (therefore, genes become rearranged)

• Point mutations – a single mutation where one organic molecule in RNA/DNA is replaced with another (e.g., cytosine is replaced with thymine in the DNA sequence)

4 Types of biopsies and what they are

• Needle aspiration (FNA or Core Needle) – removes a portion of abnormal appearing tissue/fluid; often done under CT or US guidance

• Exfoliative cytology – scraping of cells/secretions from body surfaces (least invasive). E.g., pap smear for cervical cancer

• Incisional biopsy – part of the tumor (tissue) is excised

• Excisional biopsy – total tumor + margin of surrounding tissue is excised. E.g., lumpectomy for breast cancer

What is a pathology report?

• Document that contains the diagnosis and description of the tissue sampled

What 8 things are included in pathology report?

1. Patient information (name, birth date, biopsy date)

2. Gross description of tissue (color/size as seen by the naked eye)

3. Microscopic description of tissue (how the sample looks under the microscope)

4. Diagnosis (tumor/cancer type and grade)

5. Tumor size/extent into tissues

6. Tumor margins – edge of tissue (positive, negative, or close = neitherpositive or negative)

7. Presence of tumor markers?

8. Pathologist's signature/name of laboratory

What are tumor markers (biomarkers) and how are they detected? (3)

• substances present in or produced by tumors (benign or malignant) or other cells as a response to tumors that give information about the tumor

• Detected in the blood, urine, or tumor tissue

• Some are specific for certain cancer types

Why are tumor markers (biomarkers) used? (5)

• Screening

• Diagnosing

• Staging/estimating prognosis

• Guiding treatment & monitoring treatment effectiveness

• Determining disease recurrence

5 Types of tumor markers and what they are?

1. enzymes (e.g., ALP)

2. tissue receptors: proteins that bind to hormones or growth factors & affect the rate of tumor growth (e.g., estrogen & growth factor receptors)

3. cancer antigens (CA): proteins overproduced by genes when cancer is present; largest group

4 hormones: hormones secreted by the tissue where the tumor is or secreted by tissues that do not normally make them. E.g., ACTH

5. mutated tumor suppressor genes: BRCA-1 and BRCA-2

4 examples of cancer antigens (CA)

• CEA

• PSA

• CA-125

• CA19-9

2 examples of tumor staging systems

1. The American Joint Committee for Cancer (AJCC)

2. TNM – first developed staging system

What is staging and what does it determine?

• staging: evaluates extent of tumor

• determines patient’s prognosis

What is tumor grading?

• Describes tumor aggressiveness based on cellular differentiation

What is Dysplasia? (2)

• cells with a disorderly appearance or arrangement

• non-cancerous, but can turn into cancer

How is neoplasia classified/graded? (2)

• mild and moderate (can be reversible)

• severe (progresses to carcinoma in situ)

3 Rate of tumor growth generalizations

• Malignant tumors grow faster than benign tumors

• Poorly differentiated tumors grow faster than well-differentiated tumors

• Rate of tumor growth is dependent upon access to blood supply and hormonal factors

The only indisputable quality of a malignant neoplasm is:

• metastasis (Benign tumors CANNOT metastasize; Malignant tumors CAN metastasize)

3 most common metastatic sites

• liver

• lung

• bone

Metastasis depends upon what 3 factors?

• Type of tumor

• Size of tumor

• Degree of differentiation of tumor

Four ways tumors metastasize

1. Direct extension into surrounding tissues

2. Lymphatic system

3. Hematogenous (blood) system

4. Seeding (e.g., peritoneal fluid, CSF)

What is seeding and how does it occur?

• Cancer cells break away from the primary tumor and disseminate to other areas of the body

• can occur from needle biopsy (rare) or by way of normal bodily fluids surrounding organs

What is sentinel lymph node?

• first lymph node to which cancer cells are likely to spread

Wha is differentiation and the 4 different grades?

how much the tumor cells resemble their cells of origin (aka grade)

• Well-differentiated: close resemblance (grade 1)

• Moderately differentiated: sort of resembles (grade 2)

• Poorly differentiated: does not resemble (grade 3)

• Undifferentiated (Anaplastic): bears absolutely no resemblance or characteristics of cells of origin – the most aggressive type (grade 4)

Anaplastic (undifferentiated) cells demonstrate what 4 things?

Architectural anarchy:

• pleomorphism: cells grow in multiple shapes and sizes

• Hyperchromatism: nucleus of the cells looks darker (excessive chromatin) than normal under the microscope

• Bizarre nuclear shapes (larger-sized nuclei) & structures

• Atypical mitoses

What are mixed tumors and example?

• tumors composed of more than one type of neoplastic tissue but arising from only one germ layer

• e.g fibroadenoma (fibrous + glandular): most common benign breast lump in young women

Benign vs Malignant tumor of fibrous tissue

• benign: fibroma

• malignant: fibrosarcoma

Benign vs Malignant tumor of fat

• benign: lipoma

• malignant: liposarcoma

Benign vs Malignant tumor of cartilage

• benign: chondroma

• malignant: chondrosarcoma

Benign vs Malignant tumor of bone

• benign: osteoma

• malignant: osteogenic sarcoma

Benign vs Malignant tumor of blood vessels

• benign: hemangioma

• malignant: angiosarcoma

What is mesothelioma?

• malignant tumor of mesothelium

What is leukemia?

• malignant tumor of hematopoietic cells (blood)

What is lymphoma?

• malignant tumor of lymphoid cells (lymphatic)

Benign vs Malignant tumor of squamous epithelium

• benign: squamous cell papilloma

• malignant: squamous cell carcinoma

3 benign tumors of glandular epithelium

• adenoma

• papilloma: tumor with finger-like projections, grows outward

• cystadenoma: tumor that is filled with fluid (cysts)

3 malignant tumors of glandular epithelium

• adenocarcinoma

• papillary adenocarcinoma

• Cystadenocarcinoma

Benign vs Malignant tumor of Smooth muscle

• benign: Leiomyoma

• malignant: Leiomyosarcoma

Benign vs Malignant tumor of Skeletal (striated) muscle

• benign: Rhabdomyoma

• malignant: Rhabdomyosarcoma

Benign vs Malignant tumor of Melanocytes

• benign: nevus

• malignant: melanoma

5 examples of malignant tumors that sound benign

1. Lymphoma

2. Melanoma

3. Mesothelioma

4. Multiple myeloma

5. Seminoma

What is a Polyp?

• benign tumor that projects upward from a mucous membrane (colon cancer)

What is follicular adenoma?

• benign tumor of the thryroid: Solitary, circumscribed nodule; cells are well differentiated