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Pathology
Glossary
 Differentiated: how mature (developed) the cancer cells are in a tumor.
Differentiated tumor cells resemble normal cells and tend to grow and spread at a
slower rate than undifferentiated or poorly differentiated tumor cells, which lack
the structure and function of normal cells and grow uncontrollably.
 Carcinogens: The process by which normal cells are transformed into cancer
cells by changing the code on DNA.
The Pathology of Cancer
 Cancer is considered to be a disease of the cell, in which the normal mechanisms
of the control of growth and proliferation are disturbed.
 Results in morphologic changes in the cell and ultimately a change in tissue
pattern.
 Pathologists can diagnose malignancy based on these changes, but must
distinguish from other diseases as well.
o Benign tumors
o BPH: Benign prostatic hypertrophy. A benign (noncancerous) condition in
which an overgrowth of prostate tissue pushes against the urethra and the
bladder, blocking the flow of urine. Also called benign prostatic
hypertrophy and benign prostatic hyperplasia.
Types of Biopsy
 Incisional biopsy: A surgical procedure in which a portion of a lump or
suspicious area is removed for diagnosis. The tissue is then examined under a
microscope. (Small sample: soft tissue, bone, benign tumors)
 Excisional biopsy: A surgical procedure in which an entire lump or suspicious
area is removed for diagnosis or treatment. The tissue is then examined under a
microscope. (Lumpectomy: Surgery to remove the tumor and a small amount of
normal tissue around it.)
 Exfoliative cytology: sample of cells obtained by scraping the surface (Pap
smear: A procedure in which cells are scraped from the cervix for examination
under a microscope. It is used to detect cancer and changes that may lead to
cancer. A Pap smear can also show noncancerous conditions, such as infection or
inflammation.)
 Needle aspiration: needle inserted into tumor to obtain sample for diagnosis,
(often uses CT or ultrasound for guidance)
o Fine: extract cells
o Core: extract tissue
 Endoscopic: tumor visualized through endoscope and a piece of tumor is
removed with forceps; commonly used for tumors of the GI tract, GU tract, and
respiratory tract.
Malignant vs. Benign Neoplasms
 Malignant
o Invasive: Cancer that has spread beyond the layer of tissue in
which it developed and is growing into surrounding, healthy
tissues. Also called infiltrating cancer.
o Destructive
o Differentiation
o High mitotic rate
o Can disseminate
o Aneuploid: Having a chromosome number that is not a multiple of
the haploid number for the species. Many types of tumor cells are
aneuploid; abnormal DNA content in the nucleus (measured using
flow cytometry)

Benign
o
o
o
o
o
o
Encapsulated
Noninvasive
Well-differentiated: low grade
Normal mitosis
Do not spread
Diploid: normal DNA content; having two sets of chromosomes or
double the haploid number of chromosomes in the germ cell, with
one member of each chromosome pair derived from the ovum and
one from the spermatazoon. The diploid number, 46 in humans, is
the normal chromosome complement of an organism's somatic
cells.
Carcinogenesis
 Carcinogenesis: the process by which one or more normal cells undergoes
genetic alterations that result in malignant transformation. It involves exposure of
cellular DNA to carcinogens, substances or agents that can damage genetic
material.
o Viral carcinogenesis
 HPV: Human Papilloma virus: A member of a family of
viruses that can cause abnormal tissue growth (for example,
genital warts) and other changes to cells. Infection with
certain types of HPV increases the risk of developing
cervical cancer.
 EBV: Epstein Barr Virus: A common virus that remains
dormant in most people. It has been associated with certain
cancers, including Hodgkin’s and nasopharyngeal
carcinoma.
 Hep B: A virus that causes hepatitis (inflammation of the
liver). It is carried and passed to others through blood or
sexual contact. Also, infants born to infected mothers may
become infected with the virus.

HIV: Human immunodeficiency virus. The cause of
acquired immunodeficiency syndrome (AIDS – lymphoma,
Kaposi’s sarcoma).
o Chemical carcinogenesis: tobacco, pesticides, asbestos
o Radiation carcinogenesis: sunlight, tanning beds, ionizing radiation
 Long latent period
Genetics
 Oncogenes: A gene that normally directs cell growth. If altered, an oncogene can
promote or allow the uncontrolled growth of cancer. Alterations can be inherited
or caused by an environmental exposure to carcinogens; genes that, when
activated, can enhance tumor progression; presence of or over activity of these
genes can stimulate the development of cancer
 Tumor-suppressor genes: A type of gene that helps control cell growth.
Blocking the action of tumor suppressor genes may lead to cancer; normal genes
whose absence can lead to cancer
o P53 gene: A tumor suppressor gene that normally inhibits the growth of
tumors. This gene is altered in many types of cancer. Triggers cell suicide:
apoptosis
 DNA repair genes: correct errors in DNA before it’s duplicated
Classification of Neoplasms
 Benign
o Hyperplasia: An abnormal increase in the number of cells in an organ
or tissue. excessive rate of cell division (ex: callus)
o Dysplasia: Cells that look abnormal under a microscope but are not
cancer; decrease of normal arrangement and cell structure
 Increased number of cells
 Can reverse or become malignant
 Shape deformed
o Carcinoma in situ: A group of abnormal cells that remain in the tissue
in which they first formed. These abnormal cells may become cancer
and spread into nearby normal tissue. severe dysplasia; remains at site
 Will turn into cancer if not treated

Malignant
o Sarcoma: A cancer of the bone, cartilage, fat, muscle, blood vessels,
or other connective or supportive tissue connective tissue
(mesenchymal: Refers to cells that develop into connective tissue, blood vessels,
and lymphatic tissue)
 Angio: vessel
 Osteo: bone
 Chondro: cartilage
o Carcinoma: Cancer that begins in the skin or in tissues that line or
cover internal organs. epithelium (lining of surfaces)
 Squamous cell (Head and Neck, lungs)

Basil cell: small, round cell found in the lower part (or base) of the
epidermis, the outer layer of the skin.
 Adenoid – gland (prostate, pancreas)
o Lymphoma Cancer that begins in cells of the immune system. There
are two basic categories of lymphomas. One kind is Hodgkin
lymphoma, which is marked by the presence of a type of cell
called the Reed-Sternberg cell. The other category is non-Hodgkin
lymphomas, which includes a large, diverse group of cancers of
immune system cells. Non-Hodgkin lymphomas can be further
divided into cancers that have an indolent (slow-growing) course
and those that have an aggressive (fast-growing) course. These
subtypes behave and respond to treatment differently. Both
Hodgkin and non-Hodgkin lymphomas can occur in children and
adults, and prognosis and treatment depend on the stage and the
type of cancer.
o Leukemias: Cancer that starts in blood-forming tissue such as the
bone marrow and causes large numbers of blood cells to be
produced and enter the bloodstream.
Tumor grading: The grade of a tumor depends on how abnormal the cancer cells look
under a microscope and how quickly the tumor is likely to grow and spread. Grading
systems are different for each type of cancer. – more useful for diagnosis
 An evaluation of the degree of differentiation of a tumor
 Either graded numerically (1-3) or descriptively (well, moderate, poor)
 Low grade: well-differentiated; the tumor cells still resemble normal cells
 High grade: poorly differentiated or anaplastic: cancer cells that divide rapidly
and have little or no resemblance to normal cells – Grade-4, very aggressive and
radioresistant
Tumor staging: The extent of a cancer in the body. Staging is usually based on the size
of the tumor, whether lymph nodes contain cancer, and whether the cancer has spread
from the original site to other parts of the body.
 No microscopic evaluation needed
 Evaluation of the extent of the tumor at time of diagnosis
o T= tumor size and degree of invasiveness (1-4)
o N= regional node involvement (0-3)
o M= presence or absence of distance metastasis (0 or 1)
Dukes (ABC): A staging system used to describe the extent of colorectal cancer.
Stages range from A (early stage) to D (advanced stage).
FIGO: International Federation of Gynecology and Obstetrics: (GYN)
Ann Arbor: Hodgkin’s disease
The higher the grade or stage, the worse the prognosis
Tumor growth
 Different tumors grow at different rates, for example, cervical cancer can be in a
benign state for 10 years before becoming malignant.
 Once a malignancy occurs, the growth rate is called the doubling time = time it
tales for all cells to divide
o It is estimated that 30 doubling times are needed for a tumor to reach 1
cm in diameter. Usually detectable at this time
Patterns of Growth
 Benign
o Grow in a spherical manner and are symmetrical
o Compress and push normal tissue, demonstrating a capsule around
them
 Malignant
o Expand, invade and destroy normal adjacent tissue
o Have irregular and poorly defined borders
o Can ulcerate: To develop an ulcer; become ulcerous
o -Or fungate: To grow rapidly like a fungus
Dissemination
 Direct extension
 Lymphatics – carcinomas
 Hematogenous – sarcomas
 Seeding
Toxoplasmosis: A single-celled parasite, few have symptoms because a healthy
person's immune system usually keeps the parasite from causing illness, pregnant
woman should be cautious of clean liter boxes. Symptoms- flu-like blindness, brain
damage
P carinii Pneumonia
Blebs: large blister filled with serous fluid