Posted January 1, 2005
The Pathology Report series is written for your patients, to
help them better understand the pathologist’s report.
Melanoma is a form of skin cancer that can be lethal but can also
be cured if caught very early. Malignant melanoma in situ (MMIS)
is the earliest form of malignant melanoma. It is called in situ
because it has not penetrated beneath the outermost layer of the
skin, known as the epidermis. If the melanoma cells extend into the
next layer, known as the dermis, it is called malignant melanoma
(MM). Once the cells grow downward into the dermis, the cancer will
come into contact with lymph and blood vessels. The thicker the melanoma,
the greater likelihood that it could spread through these vessels
to distant sites; this process is called metastasis. Removal of the
lesion before it enters the deep layers of the skin is crucial for
achieving a cure.
People who regularly check moles on their skin may have a lower
risk of developing advanced melanoma. Any suspicious lesion should
be examined by a physician. A mnemonic device, ABCD, is used to describe
several features that help distinguish melanomas from non-cancerous
growths: Asymmetry, Border Irregularity, Color
Variation and Diameter. MMIS and MM generally grow in an
irregular, asymmetric fashion, have indistinct borders, contain various
colors within the lesion and have a diameter of 6 mm (about the size
of a pencil eraser) or larger.
The greatest risk factor for melanoma is intense exposure to sunlight
and ultraviolet radiation. People with light skin, blue, gray or
green eyes, red or blonde hair and lots of freckles are at a higher
risk for developing melanoma. The risk increases for those who are
easily sunburned and is especially high for those who experienced
severe sunburns during childhood. Patients who have a family history
of melanoma are also considered to be at an increased risk.
If melanoma is detected as MMIS, the 5-year survival rate is 95%.
On the other hand if the cancer is more advanced, survival drops
below 60%. Therefore it is not only important to prevent development
of melanoma through the use of sunscreen and protective clothing,
but to catch these growths early. Patients are advised to check their
entire body every month, and those with risk factors should see a
physician once a year for a full-body skin screening.
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NewsPath® Editor: Megan
J. DiFurio, MD, FCAP
This newsletter is produced in cooperation with the College of American
Pathologists Public Affairs Committee and may be reproduced in whole or
in part as a service to the medical community. Copyright © 2006 by
the College of American Pathologists.
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