And melanoma skin cancer
Oncology / / April 18, 2016
Alternative names melanoma - skin cancer, squamous cell carcinoma, basal cell carcinoma, actinic keratosis.
Skin cancer develops in the cells of the skin and is divided into two main groups:
- nonmelanoma, including basal cell carcinoma;
- squamous cell carcinoma.
Melanoma is considered the most dangerous form of skin cancer.
Different types of skin cancers developing in different cells of the skin.To understand this, take a look at the structure of the skin.The skin is the largest organ in the body.The skin and its components (hair, nails, sweat and sebaceous glands) make up the coating system.One of the principal functions of skin is to protect - it protects the body from external factors - such as bacteria, chemicals, and temperature.The skin contains a secret that can kill bacteria.The pigment melanin provides a chemical defense against ultraviolet radiation, which can damage skin cells.The skin also helps to control the body temperature.
skin consists of several layers.The outermost layer is
melanocytes. cell layer between the epidermis and dermis called melanocytes, produces a brown-black skin pigment - melanin, which determines the color of the skin and hair.Melanin also helps protect the body from harmful radiation from the sun.As a person, melanocytes often grow and multiply.They form clusters, which appear on the surface of the skin as a small, dark, flat or dome-shaped spots.It is usually harmless moles or "liver spots."
When cell proliferation (growth of body tissue by propagation cell division, increased cell numbers or only genomes at polyploidy by mitosis, leading to an increase in tissue in contrast to other methods of increasing its weight) formed benign stains, commonly referred to as moles or nevi.Sometimes, however, the pigment cells go out of control and become cancerous - and thus life-threatening melanoma.
Melanoma is less than 5% of all skin cancers, but in most cases it leads to death from skin cancer.
first melanoma cells are found in the epidermis and upper dermis.However, once they grow deeper in the dermis, the cancer can come into contact with the lymph nodes and blood vessels, and then spread to other parts of the body.The thicker melanoma, the greater the likelihood that it can spread to distant sites.It is important to remove the melanoma lesion before it reaches the deep layers of the skin.
types of melanoma
- Surface spread of melanoma. Surface spread of melanoma is the most famous and most curable type of melanoma.This flat, asymmetrical, uneven painted formation that normally grow outwardly through the skin surface.Surface spread of melanoma accounts for approximately 70% of melanomas.In men, they appear most often on the back.In women melanoma often you can be seen on the back of the legs.
- nodal melanoma. nodal melanoma appears as a fast-growing brown or black lump, the technical characteristics which are not always consistent with the definitions described above.It is important to check this type of melanoma because it is connected with the flash of other tumors.Nodal melanoma is about 5% of all melanomas.It usually occurs on the trunk or extremities.
- Malignant lentigo. Malignant lentigo (freckles sometimes called Hutchinson) usually occur in older adults and characterized by flat, mottled, yellow-brown freckles, like spots with irregular borders.These lesions often appear on the face or other exposed areas of the skin to the sun and usually grow slowly over 5-15 years before the emergence of cancer.Malignant melanoma lentigo make up 4-15% of melanoma.
- acre Lentiginus melanoma. Although rare, Acre Lentiginus Melanoma Melanoma is the most common among the African and Asian populations.It usually appears in the form of dark spots on the palms, soles, fingers or feet, under the nails or toe nails, or mucous membranes.
There are several other types of melanomas, but are relatively rare.
stages of melanoma
melanoma cells usually spread first through the lymphatic vessels and glands.melanoma cells can also spread through blood vessels of different organs, in conducting cancer liver, lungs, brain or other areas.
melanoma tends to grow in several stages most melanomas usually grow and spread throughout the skin surface.At this early stage, which can last for 1-5 years or longer, removal growing melanomas has an excellent chance.Nevertheless, there is a possibility that some of these are invasive melanomas (inner, deep), and they should be treated more harshly.
lesions that are domed, at least part of their surface, shows that there was a downward growth of cancer cells.In some cases, this growth is very fast, in a matter of weeks or months.Any suspicious lesions should be checked right away, especially if it has grown rapidly, partially flat or partially raised.
General location melanoma in men in the areas of: head, neck, torso.General location of melanoma in women in the areas of: chest, legs.
However, melanoma can affect any area of the skin.A person can not notice melanoma, if they occur in areas that are hard to see - such as the scalp or back.
Less common sites for melanoma: fingers, genitals, lips, soles of the feet, the place under the fingernails, toenails.
Brown defeats under his nails, which next to the skin and do not heal for a long time, may be a sign of melanoma.
Occasionally melanoma can appear in the mouth, on the iris of the eye, the retina back of the eye, where they can be found during dental or eye examinations.Although quite rare, melanoma can also develop in the mucous membranes such as the vagina, esophagus, anus, urogenital tract and small intestine.
other types of skin cancer (non-melanoma)
Other types of skin cancers called non-melanoma skin cancer.The two most common types are called basal cell carcinoma and squamous cell carcinoma.
Basal cell carcinoma
Basal cell carcinoma begins in the lower part of the epidermis, in round cells called basal.Basal cell carcinoma is the most common form of skin cancer.Nevertheless, this type of cancer is likely to be much less fatal than melanoma.The mortality rate of non-melanoma skin cancer in 30 years has decreased by about 30%.
Basal cell carcinoma usually develops later in life in the parts of the body that received the most exposure to the sun - such as the head, neck, back, and especially the nose.However, some cancers basal cells appear in areas not exposed to the sun.
basal (core located at the bottom of facing or related thereto) cells (morphologically lower specific structure cell or organ, through which they are attached to the carrier body, at the base of epidermal cells adjacent to the dermis) cancer usually appear as circular areasthickened skin, which does not change the color or causes pain, itching.
defeat extends and develops very slowly, with a slightly raised edge thickening, which can be translucent and smooth.Sometimes basal cancer cells have a color similar to malignant melanoma.
In the end, they become the center of hollowed and covered with a thin skin, which can become diseased and open.
form, known as aggressively growing basal cell carcinoma, the scar looks like a rigid base.For this type of cancer must be treated very seriously.
Basal cell carcinoma is a cancer (malignant) tumors of the skin, involving the basal cells of the skin.The basal cells of the skin usually appear on areas of skin that are regularly exposed to sunlight or other ultraviolet radiation.After a suspicious lesion found for the diagnosis of basal cell cancer biopsy needed.The treatment varies depending on the size, depth and location of the cancer.
Basal cell cancer is sometimes difficult to distinguish from benign skin diseases.For example, sometimes they occur in the skin are invisible, where they can look like a normal nevus, cyst or pimple.They can be particularly difficult to distinguish from benign cysts when they occur near the eyes.
Typically, the basal cells grow slowly.They are rarely fatal.Most basal cell cancers should not be considered as an emergency.However, the belated treatment can lead to injury.Therefore, they should be removed as early as possible.Basal cell cancer.likely include those which give rise to scar more than 1 cm, and those located in the cheek, the nose, throat, ear lobe, eyelids.
Some studies have shown that people with basal cell carcinoma may have a higher risk of a second cancer, including melanoma - cancer of the lips, salivary glands, larynx, lung, breast, kidney and non-Hodgkin's lymphoma.Those who are at increased risk of basal cell carcinoma, apparently, men under the age of 60 years.
Squamous cell carcinoma and Bowen's disease
Squamous skin cancer is even less common than basal cell cancer.Squamous cell carcinoma of the skin develops from the flat-type cells called keratinocytes and under the top layer of the epidermis.Most cases of squamous cell cancers occur on the sun.It affects exposed skin - especially the forehead, temples, ears, neck, back and arms.People who have spent a lot of time in the sun baths can develop squamous cell carcinoma on the lower legs.Squamous cell carcinoma is more common than basal cell cancer in African-Americans and Asians, and more - in men than in women.
Although squamous skin cancer can usually be completely removed without the risk of proliferation, it is likely more aggressive than basal cancer and can spread to different parts of the body.
Types of squamous cell carcinoma:
Squamous cell carcinoma in situ (also called Bowen's disease) is the earliest form of this type of cancer, when the cancer has not invaded surrounding tissues.Cancerous areas look like large reddish spots, scaly and crusty.
Invasive squamous cell carcinoma has a high chance of spreading (metastasis).cancer of the skin lesions can grow quickly (within a month) or slowly (one year).In the end, they can break into the open wound (ulceration).
Getting early treatment is important because squamous cell carcinoma more frequently than basal, apply to local lymph nodes.
Squamous cell carcinoma is likely to apply to:
- deep lesions, or patches with poorly defined borders;
- large lesions (greater than 2 cm in diameter);
- recurrent lesions;
- arms, neck, earlobe, eyelids, lips;
- areas of skin that have been treated with radiation or exposed to cancer-killing chemicals (chemotherapy).
People who had basal cell or squamous cell skin cancer are faced with a twofold increase in the risk of developing other types of cancer, including bladder cancer, breast cancer in women, leukemia, lung cancer, melanoma, non-Hodgkin's lymphoma, cancertesticular and prostate cancer in men.
In young people with non-melanoma skin cancer is higher risk of developing other cancers.
precancerous lesions of the skin
- Actinic keratosis (also called "solar keratosis") - skin lesions caused by too abundant sunshine.There is a slightly increased risk of skin cancer patients with these lesions, but the risk of conversion into one specific cancer actinic keratosis is low.Increased risk of cancer may be associated with the sun, actinic keratoses and nonmelanoma skin cancer.
Actinic keratosis occurs after many years of exposure to the sun - basically exposed skin - face, neck, backs of hands and forearms, upper chest and upper back.Men keratosis can develop on the edge of the ear.
- keratoacanthoma - they resemble squamous cell carcinoma, but not malignant.Most of them originate from the sun exposed skin - usually the hands or face.They are usually flesh-colored or slightly red.When first developed, in the early stages, keratoacanthoma - smooth, domed.Within a few weeks, they can grow quickly - usually in 1 or 2 centimeters.Some - the size of a quarter less and can be ugly.In the end, they stop growing and become with the outside edge of the fabric, sometimes within the solid.
keratoacanthoma almost always leave scars after healing.In addition, about 25% of them develop into squamous cell carcinoma - most often in the elderly, and the sun on exposed skin.It is recommended to remove them surgically (sometimes radiation).It may also be treated with 5-fluorouracil - cream or injection.
Causes of melanoma and skin cancer
sun is the main cause of premature skin aging (photoaging) and skin cancer.
Long-term, repeated exposure to sunlight are likely responsible for the most undesirable effects of aging of the skin, including basal cell and squamous cell cancers.Melanoma is more likely to be caused by the intense sunlight at an early age.
- Ultraviolet (UV) alpha and beta radiation. When sunlight penetrates the upper layers of the skin, the ultraviolet radiation strikes beta DNA in skin cells and damages it.Beta radiation is the main type of radiation responsible for sunburn.First, it affects the outer layers of the skin.This type of UV light is most intense at midday when sunlight is most striking.Alpha - radiation penetrates more deeply and efficiently.While glass (machines, buildings, points) filters beta-rays, it does not protect against the alpha radiation.
- The harmful effects of UV radiation.Alpha - beta radiation and cause damage, including genetic injury, wrinkles, decreased immunity against infection, aging skin diseases and possibly cancer.
some ways, it may develop cancer, and certain skin action to defend themselves against DNA damage:
- oxidation and antioxidants. UV light stimulates the production of oxidants, also referred to as "free radicals."This unstable molecules which make conventional chemical processes in the body, capable of damaging the cells in the body and even alter DNA.This contributes to the aging process and sometimes leads to cancer;
- Defective DNA repair and protective enzymes. Some types of skin cancers are caused by "cracks" in the body's mechanisms that help restore DNA damage.For example, dry skin pigment is a rare genetic disease in which the body can not repair the damage caused by ultraviolet light.As a rule, a number of skin enzymes that protect against damage;
- immune defense.Specific immune skin protection factors, including white blood cells known as "T-lymphocyte" and specialized skin cells known as "Langerhans cells".These immune system cells attack the developing cancer cells at the earliest stages.