Conditions: Melanoma of The Skin

(Cutaneous Melanoma)

what is melanoma?

Melanoma is a a cancer arising from pigment producing cells called melanocytes, and usually occurs on the skin, but may occur in the digestive tract, nose or sinuses, and eyes. Overall, melanoma is the most dangerous type of skin cancer owing mainly to its notable ability to spread to lymph nodes or other organs. The risk to life of a given melanoma may be predicted by specific features. Early melanoma without spread has a cure rate nearing 99%. When melanoma has spread to surrounding lymph nodes, the cure rate drops to 65%, and when it has spread to other organs (distant spread), the cure rate is about 25%. Given the significant drop in survival based on extent of spread, physicians identify and use several characteristics from the initial evaluation and biopsy to predict spread, primarily the depth of the melanoma.

What are the risk factors for melanoma?

The primary cause of melanoma is ultraviolet light exposure, which may be from the sun or other sources (such as a tanning device). Risk is greater in individuals with light colored skin, many moles, a weakened immune system, and a family history of melanoma.

What does a melanoma look like?

How is a melanoma diagnosed?

A biopsy is necessary to diagnose melanoma. Some or all of the suspicious lesion is removed and subsequently examined microscopically by a pathologist. In many cases, special stains of biopsy specimen may be necessary to confirm the diagnosis.

What other information does a biopsy provide?

Besides the diagnosis of melanoma, additional information from the biopsy can predict likelihood that the cancer has spread to other area(s) of the body. When a biopsy specimen consists of the full thickness of a melanoma, an accurate assessment of the depth of invasion may be made. This is the strongest predictor of spread to other sites. Surface ulceration and/or the presence of satellite lesions (smaller spots surrounding the main melanoma) may be noted at the time of biopsy, and also indicate a more aggressive cancer. Other factors that a biopsy specimen demonstrate under a microscope include the number of dividing cells per square millimeter.

When is imaging necessary?

When examination in clinic does not reveal any enlarged lymph nodes and when the initial biopsy suggests low risk for spread, no imaging is indicated. If enlarged lymph nodes are present, or when biopsy features suggest higher risk for spread, imaging, such as CT, PET-CT or MRI scanning is indicated.

What is sentinel node biopsy? When and why is it performed?

When a melanoma biopsy suggests a likelihood that it has spread, but when clinical evaluation does not show apparent spread, the surgical removal of one or a few targeted lymph nodes can be very informative. This technique is based on the observation that a given patch of skin drains to one or a few specific nearby lymph nodes. Identifying and removing the lymph node(s) that a certain skin area drains is called sentinel lymph node biopsy. This procedure is minimally invasive and provides the most accurate assessment of whether a melanoma has spread. If the sentinel lymph node biopsy is negative (meaning no melanoma is found in the removed lymph node or nodes), this strongly suggests (but does not prove) that no spread has yet occurred. Alternatively, if the sentinel lymph node biopsy is positive (meaning melanoma is found in a removed lymph node), spread has occurred at least to one lymph node. While removing one or more sentinel lymph nodes can, in some cases, remove the only area of spread that has occurred, a positive sentinel lymph node biopsy indicates that spread to other lymph nodes or organs is fairly likely. This situation informs the patient and physician of chances of death and therefore may indicate need for additional treatment to try to improve outcome.