Melanoma In Situ

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After completing a thorough lab analysis of your recent skin biopsy, a specialized doctor called a pathologist reported a diagnosis of melanoma in situ, which is the earliest stage of melanoma skin cancer. Melanoma is the least common type of skin cancer, accounting for just 4% of cases, but it is the most aggressive form. However, melanoma is generally curable when found and treated in its earliest stage.

About the Condition

The skin is the largest organ of the body. Its top layer is the epidermis, which contains three types of cells that can become cancerous: melanocytes, basal cells and squamous cells. The main purpose of the epidermis is to provide protection against the environment. The second layer of the skin is the dermis, which supplies blood, oxygen, strength and support. Underneath the dermis is the hypodermis, or subcutaneous fat layer, which provides an ongoing blood supply to the dermis.

Melanoma in situ is the initial phase of melanoma skin cancer in which the cancerous, or malignant, cells are confined to epidermis, the uppermost layer of the skin. The term "in situ" refers to the cancer being located "in one site."

The condition occurs when the melanocytes — cells that give the skin its color — do not develop and die in their normal manner because of damage from long-term ultraviolet (UV) light exposure, usually from the sun. The extra cells that result form a malignant growth, or tumor.

People with fair skin, blonde or red hair and blue, green or gray eyes are at a higher risk for melanoma in situ. However, people who have darker skin and eyes can also develop the condition.

Other risk factors for melanoma in situ include:

•  Having many or large moles on the skin
•  Working or spending much time outdoors
•  Having a family history of the condition
•  Using tanning beds or other UV tanning devices
•  Having a weakened immune system

If the cancer grows more deeply into the skin, it is then considered to be invasive cancer rather than in situ. In invasive melanoma, malignant cells may invade and damage surrounding areas or spread to other locations in the body (metastasize). Thus it is important to promptly treat melanoma in situ before it can progress into invasive melanoma.

Treatment Options

The treatment of choice for melanoma in situ is surgical excision, which removes the tumor along with surrounding tissue. Stitches are usually required after the procedure.

In patients who are not good candidates for surgery for various health reasons, other treatment methods may be used such as topical immunotherapy or radiation therapy. Immunotherapy involves the application of a medicated cream (imiquimod) directly onto the skin (topically) to stimulate the body's immune responses to fight the cancer. In radiation therapy, a high energy X-ray machine is used to direct radiation at the tumor.

After treatment, your doctor will likely recommend that you have periodic skin cancer screening exams to monitor your condition.

What You Can Do

You can choose to take an active role in your health and well-being. Learn as much as you can about your condition and have a list of questions ready each time you meet with your doctor.

In addition, you should take steps to prevent further skin damage and occurrences of skin cancer, which include:

•  Avoiding the sun, especially between 10 a.m. and 4 p.m. when UV rays are the strongest
•  Using SPF 15 or higher sunscreen that contains avobenzone (Parsol 1789), titanium dioxide and/or zinc oxide, applying it 20 minutes before going outdoors and again every two hours, or immediately after swimming or sweating
•  Wearing long sleeves and pants, a wide-brimmed hat and 100% UV-blocking sunglasses when outdoors
•  Avoiding tanning salons and other UV tanning devices
•  Visiting your doctor regularly for skin checks and promptly reporting any changes in your skin

Additional Resources

American Academy of Dermatology, 888.462.3376,
American Cancer Society, 800.227.2345,
Skin Cancer Foundation, 800.754.6490,
The Melanoma Research Foundation, 800.673.1290,

This patient resource sheet is provided to you as a service of CBLPath® and is intended for information purposes only. It may not fully describe all aspects of your diagnosis and is not meant to serve as medical advice or a substitute for professional medical care. Your physician can provide you with a thorough explanation of your diagnosis and appropriate treatment options, which may vary. Only you and your physician can determine your best treatment plan.

Updated 10.07