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SLIDESHOW
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Early Skin Cancer and Melanoma ( courtecy;- medicineNet.com )
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Ultraviolet light waves can produce mutations in the DNA of
skin cells, which in turn can lead to skin cancer
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Common Skin Cancer
Symptoms and Causes
Sunlight contains
ultraviolet light that is harmful to human skin cells. These energetic light
waves can produce mutations in the DNA of skin cells, which in turn can lead to
skin cancer. In areas close to the equator, the incidence of cutaneous cancers is
dramatically higher due to the increase in sun exposure.
The most obvious skin
cancer warning sign is the development of a persistent bump or spot in an area
of sun-damaged skin. These spots are likely to bleed with minimal trauma and
produce a superficial erosion.
Skin Cancer: Actinic Keratosis (Solar Keratosis)
Actinic
keratoses are scaling, horny, red, tender bumps present in sun-exposed areas.
They are essentially very thin skin cancers that have not yet penetrated into
deeper tissues. Large areas of skin thus exposed over years can result in what
has recently been called a cancerization field defect. Continued exposure to
ultraviolet light will likely induce invasive malignancies. Prevention and
treatment of this condition which is most common in less-pigmented people is a
significant part of medical skin care.
Skin Cancer: Actinic Cheilitis (Farmer's Lip)
Actinic
cheilitis is simply actinic keratoses affecting the mucous membranes of the
lips (vermillion border). This condition usually involves the lower lip simply
because of the angle of incidence at which the overhead light waves hit the
face. The forehead, cheeks, nose, and lower lip receive light waves
perpendicularly and are not shaded by anatomical structures like the brows
Skin Cancer: Cutaneous Horns
A
cutaneous horn is a mass of dead skin cells. Essentially they have a lot in
common with hair and nails since these are also composed of dead skin cells.
The base which generates the horn can be an actinic keratosis, a squamous cell
carcinoma, or a benign keratosis. The only way to differentiate between the
three is by performing a surgical procedure called a biopsy and having it
examined in a laboratory by a pathologist
Identifying Cancerous Moles
The
word "mole" is probably derived from a German word meaning spot. In
the context of skin, a mole is a long-lasting skin spot that is a little darker
than a freckle. Since there are a variety of benign and malignant skin growths
which fulfill this description, more precision is necessary. The number of
moles present on a particular person is most closely related to skin color and
the extent of exposure to sunlight during childhood. The average number of
moles is about 35 per person in Northern European populations.
Melanocytic
Nevus
Moles
that are melanocytic nevi (nevus singular) are local growths of melanocytes
which can be present at birth or may develop after birth well into the third
decade. They vary in color from black to flesh-colored. A melanocytic nevus can
develop into melanoma, particularly if the nevus is large. The risk of a
congenital melanocytic nevus developing into melanoma is greater for children
under 10, which account for 70% of all cases.
Atypical Moles
When
a physician examines a particular spot or mole it can appear either ordinary or
peculiar. Most of these atypical nevi -- when examined under the microscope --
are not cancer; it seems to be the new lesions that develop in adulthood that
are the ones that are most likely to be malignant melanomas.
The
term dysplastic refers to changes noted in moles that can only be appreciated
on microscopic examination. This term should only be used when describing the
microscopic appearance of a nevus or other tissue. Most atypical nevi exhibit
some degree of dysplasia under the microscope.
ABCDEs of Melanoma
In
an attempt to systemize nevus description physicians use a variety of
adjectives to describe visible alterations. To simplify things, benign lesions
are almost always uniform in color, circular in shape, and exhibit bilateral
symmetry about any axis drawn through its diameter. Malignant melanomas diverge
from this appearance to a greater or lesser extent. To help one remember the
criteria, they have been called the ABCDEs (mnemonic) of nevus description.
Another valuable consideration is the so-called "ugly duckling" nevus
which appears significantly different than all the other skin spots on the
patient
Melanoma Symptoms: 'A' Is for Asymmetry
Asymmetry
refers to the degree of similarity when one compares the appearance of each of
four quadrants produced by an imaginary cross through the middle of a
melanocytic nevus
Melanoma Symptoms: 'B' Is for Border
Border
refers to degree of circular regularity of the edge of a pigmented lesion.
Perfectly circular lesions are rarely malignant.
Melanoma Symptoms: 'C' Is for Color
Color:
The degree of uniformity of color is a measure of atypicality. The more colors
present the more likely the lesion is to be malignant.
Melanoma Symptoms: 'D' Is for Diameter
Diameter:
Although malignant pigmented lesions tend to be larger than a pencil eraser
this is one of the less reliable criteria for distinguishing melanomas.
Melanoma Symptoms: 'E' Is for Evolving
Evolving:
Malignancies by their very nature tend to change over time -- mostly by
increasing in size -- as opposed to benign lesions that are stable. Since
cancers grow in an uncontrolled way they tend to produce asymmetrical lesions.
Screening for Cancerous Moles
If
a mole looks or acts at all peculiarly it is best to have it evaluated by an
expert. This frequently is a dermatologist. Most dermatologists can tell if the
pigmented lesion is composed of melanocytes or is something quite different
with no possibility of being a melanoma. Many dermatologists now use a
hand-held magnifying device which produces polarized light to evaluate colored
melanocytic tumors. The use of this instrument improves the doctor's ability to
identify suspicious lesions.
Evaluating Potentially Cancerous Moles
The
decision on which mole needs to be examined depends on the concern the doctor
has that it may be cancerous. Since the procedure necessary to take off the
suspicious bump is simple, requiring only local anesthesia and rarely is
associated with complications, the threshold for this procedure is
appropriately low. If the lesion is melanocytic in origin and it appears at all
peculiar, exhibiting any of the features addressed in the ABCDE criteria and/or
the patient complains that the bump bleeds or is irritated or itchy, that is
often enough to trigger a biopsy.
Malignant Melanoma
Malignant
melanoma is the most deadly form of skin cancer because it tends to spread at a
very early stage to other parts of the body. The likelihood that it has spread
is most directly related to the thickness of the melanoma as measured from its
surface to its depth by a pathologist. This information is communicated to the
doctor that submitted the nevus and subsequent treatment depends on this
information.
Melanoma
Symptoms
In
addition to the ABCDEs of melanoma, there are other melanoma symptoms that may
include:
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A sore that will not heal
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Pigment that spreads from the border of a spot into the
surrounding skin
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Redness or swelling around a skin spot
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A spot that becomes itchy, tender, or painful
·
Scaliness, bleeding, or oozing from the surface of a mole
How Melanoma Cancer Develops
Although
it is possible for a previously benign mole to become malignant, most of the
time a melanoma cancer begins as a single malignant cell in previously normal
skin and then continues to grow in an uncontrolled manner.
Squamous Cell Carcinoma
Squamous
cell carcinomas begin as malignancies of living epidermal cells which grow and
invade into the deeper layers of the skin. They usually begin as an actinic
keratosis and progress over many years. Although most actinic keratoses do not
eventuate into squamous cell cancers, if one has a great many of them and they
continue to receive sufficient ultraviolet irradiation producing sufficient
mutational events, it is extremely likely that a squamous cell carcinoma will
develop. They appear as thick, keratotic bumps on sun-exposed skin which
continue to enlarge. They do not commonly spread to distant sites, but larger
lesions can do this.
Bowen Disease: Is it Cancer?
So
called "Bowen's disease" lesions are simply squamous cell carcinomas
that have not as yet penetrated into the deeper layers of the skin. They
involve the entire thickness of the most superficial living layer of the
epidermis as opposed to actinic keratoses which involve the upper half of the
epidermis. They seem to be a stage in the progression of an actinic keratosis
to an invasive squamous cell carcinoma. As such it is cancer. Bowen disease is
easily curable by cryotherapy, curettage with cautery and other methods.
Basal Cell Carcinoma
Basal
cell carcinomas arise from the layer of skin cells present along the lowest
layer of the epidermis and are the most common form of skin cancer. They are
locally aggressive so they ought to be treated before they get so large that
removal becomes difficult. The tumor has a shiny surface, is pearly white in
color, and tends to bleed quite easily. It often ulcerates
Who Is At Risk for Skin Cancer and Why?
Sunlight
is by far the most common cause of skin cancer. Most of the exposure occurs
during leisure time or sun tanning. The perceived benefits of exposure to
sunlight seem to be confined mostly to the production of vitamin D in the skin
and a belief that darker skin is more aesthetically appealing. Vitamin D
requirements can be easily satisfied with dietary supplementation.
Light-skinned individuals with blonde or red hair who live in regions near the
equator are the most at risk to develop skin cancer.
Reduce Your Skin Cancer Risk
Beyond
living a healthy lifestyle, it is important to avoid exposure to sunlight as
much as is reasonably possible. Eating a balanced diet and staying physically
active improves the body’s ability to fight free radical damage and heal.
Protecting
Your Skin
Any
time there has been a darkening of the skin after sun exposure it is a sign
that some damage has been sustained. Since the incubation period for skin
cancers and photo-aging is quite long (5 to 15 years), it may be difficult to
convince sun worshipers to head indoors.
Avoiding UV
Damage
The
use of clothing, searching for shade, and the application of effective,
broad-spectrum sunscreens are all useful behaviors in limiting sun damage.
Seeking Shade
to Avoid Skin Cancer
Shade
is the first defense against skin damage. Between the hours of 10 a.m. and 4
p.m., when the sun’s rays are at their most intense, find cover or wear a
wide-brimmed hat. The Skin Cancer Foundation recommends hats with broad brims
all around that are at least three inches wide.
lthough shade is an important
protection against skin cancer, it may still leave you vulnerable to UVB light,
which can reach skin indirectly. UV radiation can bounce off of clouds, dry
sand, concrete and other UV-reflective surfaces.
Choosing the
Right Sunscreen
Sunscreens
that are reasonably durable are currently available that block all the
wavelengths of ultraviolet light with an SPF (Sun Protection Factor) of 50. It
can help to look for the words “broad spectrum” or “multi spectrum” when
choosing a sunscreen. This indicates that both UVA light and UVB light are
being blocked by your sunscreen. Keep in mind that these phrases don’t actually
indicated how much of each ray is being blocked. Also, consider using an FDA
approved “Water Resistant (40 or 80 min.)” sunscreen if you sweat or swim in
sunlight.
Additional Information on Skin Cancer
For
more information about Skin Cancer, please consider the following:
·
Reviewed by Charles Patrick Davis, MD,
PhD on Monday, August 08, 2016
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Skin Cancer
Symptoms, Types, Images
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Sources: 
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This tool does not
provide medical advice
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