Here we are, it’s 2014 and pretty much everyone knows that sun and tanning (natural or tanning beds) cause skin cancer. Likewise, most people know if you have a spot and it is changing, or you have a spot that will not heal, or you have a mole that looks funny it needs to be checked. But if you go to your dermatologist or your general doctor and all they do is check the spot YOU are concerned about they might be missing the spot that can really hurt you. Patients routinely come to see me about something they noticed on their 
skin which usually is something completely benign and harmless. Then when I ask them about the spot that IS suspicious, they have no knowledge of it. As a dermatologist, my friends, that is my job—To check you for the obvious and the not so obvious.
So does cancer really occur where the sun don’t shine? Let’s start from the top and work our way down to get an answer to this question. Unless you are bald, you can’t easily see your own scalp. Your hairdresser or barber can and their input could save your life. As we get older and our hair thins, more sun hits the noggin, and voila, more pre cancers and more risk of skin cancer. While non-melanoma skin cancers are typically rough or gritty and often raised and crusty and usually on exposed parts of your scalp, melanoma can be smooth to start and completely concealed by hair. So looking through your scalp could potentially save your life. At home, you could use a hairdryer set to cool and with dry hair, have someone examine your scalp. Compared to other areas of the body, melanomas on the scalp are usually more serious. Why? Because they go undetected for longer periods and early detection and removal is the key to a good prognosis. This is just one reason why we check scalps. Another reason is that internal cancers can spread to your skin and the scalp is a common place for this to happen. As a dermatologist, I want to know your general medical history because it provides a framework for your examination.
Speaking of hidden areas, another is the back of your ear. I diagnose and treat a good 20 or 30 cancers a year in this location alone. If your spot is relatively smooth and small, it can go unnoticed for long periods of time. Leave a cancer on your ear and it can invade close to the cartilage, putting you at risk of the cancer penetrating a nerve or blood vessel. Once that happens, the subsequent chance of the cancer spreading to a lymph node increases. If a cancer does spread to a lymph node you then face serious surgery followed by radiation and chemotherapy. Similarly, the margin of your eyelid can also harbor a small skin cancer and should be checked. Trust me, you don’t want to have to have someone removing pieces of eyelid, so get checked!
What about your mouth? My mouth you ask? Yes, your mouth. Particularly in smokers or tobacco chewers there is the risk of oral squamous cell cancer. But oral cancer can also occur in the absence of tobacco exposure. Some people have oral HPV (human papilloma virus), the cause of warts. This too can increase one’s risk of oral cancer. This is a reason I look in everyone’s mouth even if they are surprised by my request. Eradicating a spot that is pre cancer inside your mouth could save your life!
Moving down. Let’s not forget the obvious. A lot of skin cancers DO show up where the sun shines, just in places where YOU can’t see them yourself. The most common place for melanoma in men is the back……and most guys don’t regularly look at their back. This is the reason why everyone who comes to my office is asked if I can check their back and the same reason we tell people to have their spouse or partner check for them. Another reason why we do skin checks is because many skin cancers, while showing up on visible sun exposed parts of your body, are subtle.
That barely noticeable slightly scaly small pink patch—the one that is more pink when you get out of the shower or maybe bleeds if rubbed by a towel is probably a superficial basal cell skin cancer. Yep, the one there on your upper arm, your shoulder, your shin. And speaking of skin and cancer, not all cancers on your skin come from your skin. A pink spot or hard area in the skin near or on the breast could be breast cancer, particularly if you have a history of breast cancer. Breast cancer can spread from the breast to the skin on or around the breast area.
Down we go. My buttock? I keep a bathing suit on doc, thank you very much! Well, you probably do, but did you know that people who have lots of moles, and particularly people who have lots of large moles often have them on the buttock? And just like one on their trunk can be precancerous, so too can one on the buttock. Same goes for the pubic area. This is a very common place that moles show up, even in people without a lot of moles, but particularly in those with a lot of moles. Granted, it’s not likely the sun that is the cause of these moles becoming cancer, it’s the fact that larger moles and more irregular looking moles have a greater chance of turning into cancer.
How about the groin? Certainly the sun doesn’t shine there, does it? Not usually. Even so, we see one form of cancer, called Bowen’s disease in the groin. This cancer is also called squamous cell carcinoma in situ. At least a few times a year I diagnose someone with it. In the groin, it is possible that this cancer could be from prior arsenic exposure (potentially from well water, or from living on a farm). On the penis or vulvar area this form of cancer typically is related to HPV (the human papilloma, or wart virus). In the groin, it could also be related to HPV. So, in addition to checking this area, it is why I always ask people do you have any pink flaky patches that won’t go away or pimples that won’t heal. Another cancer, even more serious, is called extramammary Paget’s disease and it too can show up around the groin, or the genitals, or the anal area. It is an indicator of an internal cancer that has spread to the skin. You certainly don’t want to be treating something that you think is fungus or yeast that isn’t getting better when in fact it’s an internal cancer manifesting in the skin.
Finally we are down to the bottom, the one you don’t sit on. Your foot. Moles can occur on the bottom of the foot or between the toes and sometimes these moles can turn cancerous, so looking between your toes and on the bottom of your foot is important and part of our complete skin check. In fact, in darker skinned races, the foot is one of the most common places for skin cancer to occur and when it does it is usually more serious. This is for the same reason that a melanoma on the scalp is more serious—it is usually not diagnosed quickly enough and time is of the essence. The longer it takes to diagnose and treat, the worse your prognosis.
The last point I’d like to make is that your complete skin check allows us a window to the inside of your body. This is much more than just looking for skin cancer. As your skin care specialist, your dermatologist is trained to connect a bruise like area near the eye to a serious blood related cancer called multiple myeloma; pink scaly patches on your hip to lymphoma; subtle swelling on your neck to a tumor in your chest; small bumps on the rim of your nose as the cause of your difficulty breathing; a rash on your fingers to possibly having ovarian cancer; thickened areas of skin on your shins to thyroid disease; hardening of the skin of your upper back to diabetes and many many more. So get a complete skin check. Your dermatologist might not only save you from an undiagnosed melanoma, he or she might discover an internal cancer and equally save your life.
Steve Wolfe
July 20, 2014
