Report: Tattoo Can Obscure Melanoma

August 2, 2013

News Review From Harvard Medical School -- Report: Tattoo Can Obscure Melanoma

Putting a tattoo over a mole or birthmark can make it more difficult to notice changes that can lead to cancer, a new report suggests. The authors discuss the case of a young man who decided to have a large tattoo removed by laser. Doctors examined him and noticed a mole under the tattoo. It did not appear to be cancerous, but they suggested removing it. The man refused. During the next seven years of treatments to remove the tattoo, doctors became more concerned about how the mole looked. Finally, the man agreed to let them remove it. The mole turned out to be a melanoma. Sixteen similar cases have been reported in English-language journals, the authors said. They said that in general tattoos should not be placed over a mole or birthmark. If they are, the tattoos should not be removed by laser. An expert told HealthDay News that laser treatments can remove the pigment in the mole, too. So both the tattoo and its removal can make it harder to see worrisome changes. The journal JAMA Dermatology published the study. HealthDay wrote about it July 31.

By Robert H. Shmerling, M.D.
Harvard Medical School

What Is the Doctor's Reaction?

Melanoma is a potentially deadly form of skin cancer. So the news that it can "hide" in a tattoo caught my attention.

There have been only a few reports of this happening. But I wonder -- as did the report's authors -- whether it may be more common than we know.

The new report appears in the journal JAMA Dermatology. A young man with a large tattoo on his chest and arms saw doctors to have the tattoo removed.  His doctors recommended at the start that a suspicious mole within the tattoo be removed.  He refused.

But as the tattoo was removed (with nearly 50 laser treatments), the appearance of the mole became clearer and more worrisome.   Eventually, the mole was removed. It was a melanoma.

The case is important for several reasons:

• The ink from the tattoo made evaluation of his mole more difficult.  Therefore, a tattoo should never be applied over a mole (at least not before the mole is thoroughly evaluated).
• Though it's unproven, there's a concern that frequent laser treatments might promote skin cancer.  So, if a tattoo is going to be removed by laser treatments, moles within the tattoo should first be evaluated and/or removed.
• We may not know how often people develop melanoma within a tattoo.   Only 16 cases have been reported, but it's possible the number is much greater.
• Tattoos are becoming much more common.  In the United States, an estimated 1 in 4 adults between the ages of 18 and 50 has a tattoo.  So the possibility of having a precancerous or cancerous mole within a tattoo may be increasing.

This report is also important because it serves as a reminder about the things you can do to prevent skin cancers, including melanoma.  And if skin cancer does develop, you can take steps to improve your chances of cure.

What Changes Can I Make Now?

Here's what you can do to help prevent skin cancer: 

• Avoid sunburn and excessive sun exposure.  This is especially important during times of peak radiation, about 10 a.m. to 3 p.m.
• Wear sunglasses, a wide-brimmed hat and clothing that covers the arms and legs when in the sun.
• Use a sunscreen with a sun protection factor (SPF) of at least 30.
• Avoid tanning parlors.  Sunless tanning creams or sprays are considered much safer. 

These measures are particularly important for those at increased risk of melanoma.  People at high risk include those who have: 

• Fair skin
• Blond or red hair
• Light-colored eyes
• A tendency to develop freckles or moles
• A family history of melanoma 

Examine your skin regularly.  If you have a suspicious mole, also called a "nevus," see your doctor.  A mole is considered suspicious if it has one or more of the "ABCDE" features: 

• A -- Asymmetry, where one side of the skin abnormality looks different from the other side
• B -- Border irregularity, in which the edge of the mole is ragged or uneven
• C -- Color variations, such as an uneven mixture of brown, black, tan or red
• D -- A diameter of more than 6 millimeters (about a quarter of an inch)
• E -- Evolution, or changes that occur over time, such as an increase in size 

Moles that remain sore, bleed or don't heal also should be evaluated by a doctor.  

A picture can be much more helpful than reading about the features that make moles worrisome to a dermatologist.  For good pictures of melanomas, check out this website (from the National Library of Medicine and National Institutes of Health). 

The best way to determine whether a mole is a melanoma is to have your doctor remove it. Then it can be examined under a microscope.  Of course, not every mole or freckle needs to be removed.  Doctors use their judgment to know which abnormal areas on the skin abnormalities are worth taking off. 

Finally, if you are thinking of getting a tattoo, choose its location on your body carefully!  Make sure you don't have any moles there.  If you are getting a tattoo removed, check for moles within the tattoo.  If you see any, get it checked out by your doctor (or a dermatologist) before you start laser treatments.

What Can I Expect Looking to the Future?

Unfortunately, melanoma is becoming more common.   So you can expect to hear much more about this type of skin cancer and ways to prevent and treat it. 

The popularity of tattoos is also on the rise. It seems likely that we will hear more reports of melanomas within tattoos.  And that could mean delays in diagnosis and treatment. 

Awareness of the dangers of excessive sun exposure has increased dramatically in recent decades.  I hope this eventually will lead to a decline in skin cancer diagnoses.  But we aren't there yet.