|
Glossary
of Dermatology Terms
Take advantage of our dermatology glossary to help
get a better understanding of your skin and skin risks.
A
B C
D
E F
G H I
J K L
M N
O P
Q R S T U V W X Y Z
Actinic
keratosis
(pl. keratoses): A lesion that may form on skin exposed
to the ultraviolet (UV) rays of the sunlight for many
years. The lesion can progress to squamous cell carcinoma,
a type of skin cancer that can spread.
ABCDs
of melanoma detection: ABCD is an acronym used to
help people remember the key characteristics of melanoma
detection — asymmetry (A), border irregularity
(B), and color within varies (C). The “D”
stands for diameter. While melanomas are usually greater
than 6 millimeters (size of a pencil eraser) when diagnosed,
they can be smaller. If you notice a mole different
from others, or which changes, itches, or bleeds even
if it is smaller than 6 millimeters, you should see
a dermatologist.
Adjuvant
therapy: Any treatment given after the first that
is intended to increase the effectiveness of the first
treatment.
Atypical
mole: See dysplastic.
BCG:
Bacille Calmette-Guérin (BCG) is a vaccine made
from a form of killed tuberculosis that is used to immunize
people against tuberculosis (TB). This vaccine is being
investigated as a possible treatment for advanced melanoma.
Biopsy:
Removal and microscopic examination of tissue from the
body for the purpose of establishing a precise diagnosis.
A biopsy is required to confirm a skin cancer diagnosis.
During an excisional biopsy, the entire skin lesion
is removed for microscopic examination. When an incisional
biopsy is performed, a portion of the skin lesion is
removed.
Basal
cell carcinoma: A type of skin cancer that arises
in the basal cells, which are located in the epidermis
(outermost layers of the skin). It can take many forms
and accounts for about 80% of all skin cancers. Basal
cell carcinoma can be locally invasive, but rarely metastasizes.
Benign:
Not malignant.
Blinded:
Term used in an investigational study, such as a clinical
trial, that means none of the volunteers know if they
are receiving the investigational treatment, standard
treatment, or a placebo (if a placebo is used). When
both the volunteers and researchers do not know who
is receiving which treatment, the study is said to be
“double blinded.”
Chemotherapy:
Use of anti-cancer medications to kill cancer cells
that survive surgery or cannot be reached by surgery.
Chemotherapy also may be used in the late stages to
reduce symptoms or the size of a tumor.
Clark
level of invasion: Classification system developed
by dermatopathologist, Wallace Clark, MD, that indicates
how deeply a primary melanoma tumor has penetrated the
skin. Five levels are used. Level I, also called “melanoma
in situ” indicates that the melanoma is confined
to the epidermis, the outermost layer of the skin. Levels
II - IV indicate that the tumor has invaded the dermis,
the middle layer of the skin, and each of these levels
corresponds to a different depth. When a melanoma is
classified as a Level V, it has invaded the subcutis,
the fatty layer under the skin.
Clinical
trial: A medical investigational study in which
humans are observed and/or treated. A study may investigate
a new treatment, prevention strategy, diagnostic method,
screening procedure, or how to improve comfort and quality
of life.
Control:
In an investigational study such as a clinical trial,
this is the group that receives the standard treatment,
no treatment, or a placebo rather than the treatment
being studied.
CT
scan: Computed tomography (CT), which is sometimes
called a CAT scan, combines x-ray and computer technology
to produce cross-sectional images of the body. Unlike
an x-ray, which images bones, computed tomography can
produce an image that shows everything in that area
of the body, such as organs, bones, and blood vessels.
These images can help detect cancer that has spread
to an organ or a lymph node.
Cytokines:
Proteins produced naturally in the body that act as
"messengers" to initiate inflammatory and
disease-fighting responses to viruses, bacteria, toxins,
injury, and malignant processes. Cytokines are in use
as anti-cancer medications.
Dermatopathologist:
A medical doctor trained in both dermatology and pathology
who uses this expertise to microscopically examine tissue
in order to diagnose skin conditions, often providing
expertise in diagnosing difficult cases.
Dermatoscopy:
Also called “surface microscopy,” “dermoscopy,”
and “epiluminescence microscopy,” this is
a noninvasive technique used by dermatologists to examine
pigmented and some non-pigmented lesions. The technique
involves using a handheld microscope-like device that
allows the dermatologist to see through the stratum
corneum (bottom of the outermost layer of skin), permitting
a detailed view of structures within the skin that are
usually invisible to the unaided eye. Dermatoscopy can
aid in early detection, help determine which skin lesions
should be biopsied, and assist surgeons in determining
how much normal-looking skin to remove.
Dermis:
The middle layers of skin, which consists largely of
collagen and elastin and supports the upper layers known
as the epidermis.
Distant:
Cancer has spread from the original tumor and beyond
the lymph nodes closest to the original tumor to other
lymph nodes and/or organs.
Distant
site: Once skin cancer spreads beyond the lymph
nodes nearest the original (primary) tumor, it has traveled
to a “distant site.” A distant site may be
an internal organ, skin not near the primary tumor,
or lymph nodes other than those closest to the primary
tumor.
Dysplastic:
An alteration in size, shape, and organization of cells.
A dysplastic nevus, also called an “atypical mole,”
is characterized by the ABCDs of melanoma detection.
Epidermis:
Outermost layers of skin.
Fine
needle aspiration biopsy: Also called FNA, this
type of biopsy is performed by inserting a long, thin
needle in order to extract a small amount of tissue.
The tissue is examined under a microscope to find out
if cancer cells are present. This type of biopsy may
be used to collect cells from an enlarged lymph node
or an internal organ, such as the liver or a lung.
Immunotherapy:
Treatment that repairs, stimulates, or enhances the
body’s own immune responses to fight established
disease. It is sometimes combined with chemotherapy.
In
situ: Skin cancer exists in the outermost layer
of skin only and is said to be in stage 0. The term
“in situ” literally means “in the original
position or place.”
Informed
consent: When a person agrees to volunteer for a
clinical trial, the person agrees in writing that he
or she has been informed about what will occur during
the study, the risks and benefits, whether or not the
study will be blinded, and other key information. A
volunteer can withdraw at any time; however, it is hoped
that every volunteer will stay for the duration of the
clinical trial.
Interferon:
Interferons are substances within the immune system
that are produced in response to infection. One type,
interferon-alpha, is FDA-approved for treating melanoma
in certain stages when used along with another therapy,
such as surgery. In these stages, interferon-alpha injections
can help prevent recurrence and increase the likelihood
that all cancer is eliminated.
Interleukin:
Interleukins activate the “killer” activities
of specific white blood cells in the immune system.
One specific interleukin, IL-2, helps the immune cells
reproduce more quickly and is used to treat melanoma
that has spread.
Intravenous:
Within a vein or administered directly to a vein. Some
medications, such as dacarbazine (DTIC) which is used
to treat advanced melanoma, are administered this way.
Lentigo
maligna: The in situ form of lentigo maligna melanoma.
Lentigo
maligna melanoma: See melanoma.
Lymph
node: Part of the immune system, lymph nodes are
small bean-shaped glands found throughout the body.
The glands trap bacteria, viruses, and other foreign
substances, such as cancer cells. Lymphocytes, a type
of white blood cell, work to destroy the foreign substances.
Clusters of lymph nodes can be felt in the neck, groin,
and under the arms. In these areas, the lymph nodes
can swell noticeably when fighting foreign substances.
Malignant:
When referring to cancer, the ability to grow and spread
in an uncontrolled manner beyond the local confines
of the tumor.
Margin:
Refers to the amount of normal-appearing tissue to be
removed along with the tumor during surgical excision.
The thicker the tumor, the more normal-looking skin
the surgeon removes. Margin is usually measured in centimeters.
Current recommended surgical margins for melanoma are:
Tumor
Thickness (millimeters)
In situ melanoma
less than 1.0
1.0 - 4.0
more than 4.0
Excisional Margin (centimeters)
0.5
1.0
2.0
at least 2.0
Surgical
margins may be modified for an individual patient after
considering medical or esthetic reasons. The main goal
is complete removal of the cancer.
For
an explanation of the relationship between tumor thickness
and 5-year survival rate, see thickness.
Melanocytes:
Cells that make melanin, the substance that gives skin
its color. Melanin is made in small granules, called
melanosomes, within the melanocyte. Melanin is then
transported to cells in the outer skin (keratinocytes),
where the melanin is seen as the "color" of
the skin.
Melanoma:
A cancerous tumor that arises in the melanocytes and
accounts for about 4% of all skin cancers. Four types
of melanoma are most common:
Acral
lentiginous melanoma (ALM): The most common melanoma
in dark-skinned people, it appears on palms, fingers,
toes, soles, mucous membranes, and underneath fingernails
and toenails. This tumor accounts for 2% of melanomas
in Caucasians and 50% in dark-skinned races. As the
tumor is frequently mistaken for a bruise or nail streak
in its early stages, ALM is often not diagnosed until
the later stages when the tumor is very aggressive.
Lentigo
maligna melanoma (LMM): Melanoma that develops in
a sun-induced freckle. It typically occurs on sun-damaged
skin in the elderly and may be mistaken in its early,
and most treatable, stages for a benign "age spot"
or "sun spot." It accounts for about 10% of
melanomas diagnosed in the United States. Since LMM
is so easily mistaken as a benign patch of mottled skin,
it can go undetected for years. This can be quite dangerous.
Nodular
melanoma: A very aggressive form of melanoma that
tends to grow "down" into deeper skin tissue
rather than along the surface of the skin. It accounts
for approximately 15% of diagnosed melanomas.
Superficial
spreading melanoma: This is the most common type
of melanoma, which accounts for about 70% of all diagnosed
melanomas. This melanoma usually spreads along the skin’s
surface (epidermis) and then grows "down"
into deeper skin tissue (dermis). It is curable when
it is removed before it invades the dermis.
Less
common types of melanoma include:
Amelanotic
melanoma: When this type of melanoma occurs, not enough
pigment is produced to create a dark-colored lesion.
Instead, the lesion may be skin-colored or slightly
reddish like an insect bite. It usually appears as a
pink or red nodule.
Desmoplastic
neurotrophic melanoma: This usually looks like a non-pigmented
scar-like lesion. It is suspected if a lesion, such
as a scar or keloid, is found and persists at a site
when no injury occurred to cause the lesion. The tumor
may be pigmented or non-pigmented and most commonly
appears on sun-damaged skin of the head and neck in
elderly adults.
Mucosal
melanoma: This melanoma occurs in mucosal regions of
the mouth, nose, and genitals. It may not be recognized
because it occurs in sites that are infrequently examined.
Metastasis:
The spreading of disease from one part of the body to
another. Both melanoma and squamous cell carcinoma metastasize.
Melanoma most often spreads to the lymph nodes, liver,
abdomen, lungs, bone, skin, heart, and brain.
Mohs
surgery: A highly specialized surgical technique
in which all remaining visible parts of the tumor are
excised and skin is removed layer by layer and examined
under a microscope while the patient is undergoing surgery.
Skin continues to be removed until cancer is no longer
detected. Not necessary for removing all skin cancers,
it may be used when the primary tumor is located on
the face or another area where it is essential to preserve
as much healthy tissue as possible, the tumor is large,
it is difficult to determine where the cancer ends,
or the skin cancer has recurred.
Mole:
See nevus.
Nevus
(pl nevi): What dermatologists call a “mole,”
this usually pigmented skin lesion may be present from
birth, but most often appears later in life. By age
3, approximately 80% of children will have at least
one mole. There are dozens of different types of moles,
of many shapes, colors, and sizes. Most moles are not
cancerous. Occasionally, a mole may become a cancerous
growth.
Open
biopsy: An incision is made in order to surgically
remove tissue so that it may be examined under a microscope.
This type of biopsy may be performed when a patient
has melanoma and a lymph node near a melanoma feels
hardened or enlarged. The lymph node in question is
surgically removed and examined under a microscope to
see if it contains melanoma cells.
Palliative
care: Relieves symptoms and improve a patient’s
quality of life, but does not treat the disease.
Precursor:
A lesion that has the potential to develop into skin
cancer.
Primary
tumor: The first appearance of a tumor. In skin
cancer, there may be multiple primary tumors.
Recurrent
tumor: Tumor that was treated but has returned.
Regional:
Cancer that has spread beyond the site of the primary
tumor to nearby lymph nodes and sometimes tissue/organs
close to the primary tumor.
Risk
factor: A attribute that increases the likelihood
that something will occur. Personal risk factors for
skin cancer include fair skin, especially when combined
with blond or red hair and blue, gray, or green eyes;
long-term unprotected exposure to sunlight; tendency
to freckle; tendency to sunburn rather than tan; atypical
moles; and personal history of skin cancer.
Sentinel
lymph node biopsy: A diagnostic surgical procedure
used to find out if the melanoma has spread to the lymph
nodes. It involves the surgeon identifying the first
lymph node, known as the "sentinel node,"
to receive lymph draining from the site of the primary
tumor. The sentinel node is found by injecting radioactive
material and/or dye into the skin near the tumor and
tracing the flow of lymph from the site of the tumor
to the local and regional lymph nodes. Once the sentinel
node is identified, it is surgically removed and sliced
into sections for laboratory analysis to determine if
cancer cells are present. Sometimes, the surgeon will
remove two or three nodes.
Squamous
cell carcinoma: Skin cancer that forms in the flat,
scale-like skin cells of the epidermis called the squamous
cells. It accounts for approximately 16% of all skin
cancers. This cancer can metastasize and cause death.
Stage:
How far the cancer has advanced. The staging process
determines whether the cancer is confined to the primary
tumor or if it has progressed to the lymph nodes or
distant organs.
Subcutis:
Literally, this means “beneath the skin.”
The subcutis also is defined as the bottom layers of
skin. These layers consist mostly of fat cells. Blood
vessels, nerve fibers, and muscle fibers also are found
in the subcutis. Thickness of the subcutis varies throughout
the body and depends on the amount of fat present. Therefore,
the subcutis is much thinner on the eyelids than the
buttocks.
Superficial
spreading melanoma: See melanoma.
Thickness:
In 1975, Alexander Breslow, MD, observed that the depth
of a tumor (how deeply the tumor extends into the skin)
correlates to the 5-year survival rate after surgical
removal of the tumor. This has come to be known as “Breslow’s
thickness,” which is documented in the table below:
Breslow
Thickness (millimeters)
less
than 0.76
0.76-1.50
1.51-2.50
2.51-4.0
4.1-8.0
more than 8.0
Ulceration:
A break in the surface of a skin cancer tumor, which
is often only seen under the microscope. When such a
break occurs, the tumor is said to be “ulcerated.”
Vaccine
therapy: A type of immunotherapy. Still experimental,
some patients with advanced melanoma are receiving a
vaccine, which is similar to the vaccines that protect
us against viruses, in hopes that the small amount of
melanoma injected into the patient will enable the body
to attack the melanoma.
|
