Skin cancer
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(
ICD-O 8010-8720)| ICD9 = , |
Skin cancer is a
malignant growth on the
skin, which can have many causes, including repeated severe
sunburns or long-term exposure to the
sun. Skin cancer generally develops in the
epidermis, the outermost layer of skin, so a tumor is usually clearly visible. This makes most skin cancers detectable in the early stages. There are three common types of skin cancer each of which is named after the type of skin cell.
The most common types are
basal cell carcinoma (BCC) and
squamous cell carcinoma (SCC) which may be locally disfiguring but unlikely to spread to other parts of the body. The most dangerous type is
malignant melanoma, which can be fatal if not treated early, but forms only a small proportion of all skin cancers.
Skin cancer is an increasingly common condition, in part attributed to increased exposure to
ultraviolet radiation. The increased exposure is mainly due to the recent popularity of
sun tanning (
sun bathing). Lighter-skinned individuals are more vulnerable. In the
United States, about one out of every three new cancers arises from skin. Skin cancers are often curable. Barriers which reduce UV exposure are effective in preventing skin cancers (clothes, hats, creams, lotions).
Minor surface skin cancers are readily treatable by simple
surgery, but if the cancer is allowed to grow then it will penetrate through the layers of skin and affect the
lymphatic system. It may also
metastasize and spread to other parts of the body.
Skin cancers which are aggressive, recurrent, or located upon 'high risk sites' of the body (central face, scalp, ears, genitalia) may require more advanced surgical approaches such as
Mohs' micrographic surgery to achieve high cure rates.
There are a variety of different skin cancer symptoms. These include
sores or changes in the
skin that do not heal,
ulcers in the skin, discoloring in parts of the skin, and changes in existing
moles.
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Basal cell carcinoma usually looks like a raised, smooth, pearly bump on the sun-exposed skin of the
head,
neck or
shoulders. Sometimes small
blood vessels can be seen within the tumor. Crusting and bleeding in the center of the tumour frequently develops. It is often mistaken for a sore that does not heal.
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Squamous cell carcinoma is commonly a red, scaling, thickened patch on sun-exposed skin. Ulceration and bleeding may occur. When SCC is not treated, it may develop into a large mass.
* Most
malignant melanomas are brown to black looking lesions. Signs that might indicate a malignant melanoma include change in size, shape, color or elevation of a mole. The appearance of a new mole during adulthood, or new pain, itching, ulceration or bleeding of an existing mole should be checked.
Squamous cell carcinoma is a malignant epithelial tumor which originates in epidermis, squamous mucosa or areas of squamous metaplasia.
Macroscopically, the tumor is often elevated,
fungating, or may be ulcerated with irregular borders. Microscopically, tumor cells destroy the
basement membrane and form sheets or compact masses which invade the subjacent connective tissue (dermis). In well differentiated carcinomas, tumor cells are
pleomorphic/atypical, but resembling normal keratinocytes from prickle layer (large, polygonal, with abundant
eosinophilic (pink) cytoplasm and central nucleus). Their disposal tends to be similar to that of normal epidermis: immature/basal cells at the periphery, becoming more mature to the centre of the tumor masses. Tumor cells transform into
keratinized squames and form round nodules with concentric, laminated layers, called "cell nests" or "epithelial/keratinous pearls". The surrounding stroma is reduced and contains inflammatory infiltrate (lymphocytes). Poorly differentiated squamous carcinomas contain more pleomorphic cells and no
keratinization.
1Mohs surgery*
Skin Cancer Experience Documented*Photos at:
Atlas of Pathology*
MedlinePlus: Skincancer*
SkinCancer.org*
RTAnswers - Answers to Your Radiation Therapy Questions: Skin Cancer
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Sun Safety for Babies and Children --University of Florida/IFAS Extension Department of Family, Youth and Community Sciences
