The tip of the iceberg…
By the time you have made it to your Mohs surgery appointment, typically many prior steps have already happened. Perhaps you first noticed a bump or a spot that bled when you washed your face many months before. You thought it was a pimple or a blemish, but eventually, after several months, you realized this was not your average zit, and it was time to see a doctor.
After getting a referral from your primary care doctor to see a dermatologist, you eventually underwent a biopsy that revealed basal or squamous cell carcinoma (BCC or SCC, respectively). This is an exceedingly and, unfortunately, increasingly common scenario. If you are a fair-skinned American, your chance of developing one of these cancers is about 1 in 3. In fact, the numbers of all the BCCs and SCCs sum to more than all other types of cancers combined, with estimates of over 2 million cases occurring annually in the U.S. alone. The good news is that these cancers are rarely life-threatening and can usually be managed surgically in a fairly straightforward fashion. Because BCCs and SCCs typically occur in sun-exposed areas such as the face, your dermatologist has now recommended that you see a Mohs surgeon for complete removal of the tumor.
So now you are referred to the third doctor in your journey, but when you look in the mirror, there just doesn’t seem to be anything there. There is a faint, barely noticeable, slightly depressed pink scar on the tip of your nose or on your cheek or your forehead where the dermatologist removed your biopsy; it feels better, it looks better, and so you begin to question why you should see the Mohs surgeon at all. You’re not alone, and when patients come to see me, this is almost always their first question – why should they have this procedure done if there is nothing left to see?
The truth is that, way more often than not, there are still portions of the tumor remaining. If left untreated, these small areas will likely continue to grow and may necessitate a much larger procedure. Remember that a biopsy is only a small sampling of what is there. Many things can mimic BCC and SCC, so if there is a growth on the tip of the nose or on the ear, the dermatologist has the goal of removing only enough skin for the pathologist to make an accurate diagnosis, not to remove the entire lesion. This is because if the spot does not turn out to be a skin cancer, we don’t want to leave you with an unnecessarily large scar or divot in a cosmetically sensitive area.
Despite the fact that there is not much there from the outside, BCCs and SCCs can grow in all directions – much like a beach ball – so that what you originally saw from the outside may only have been part of the tumor, and there might be just as much of the tumor under the skin as there was above the skin. While in a small percentage of cases it may be true that the biopsy has removed the tumor in its entirety, the potential repercussions of leaving tumor below the skin can be devastating. Normal skin grows over the biopsy site; meanwhile residual tumor may be lurking and go unnoticed for years. When it does finally show up again on your skin, the tiny mark on the surface may represent “the tip of the iceberg” – what was left behind grew and grew to something much larger than the original skin cancer you had when you first went to see your primary care doctor. Or worse, a SCC can travel beyond the skin to other parts of the body. At this point, what was originally a minor nuisance has now become a serious, life-threatening cancer. For this reason, we recommend additional treatment for essentially all tumors, regardless of what they look like from the outside.
The images accompanying this post are extreme examples and not typical for these cancers. However, believe your doctor when they say that there may very well be more than meets the eye when it comes to BCC and SCC. These tumors frequently can grow beyond what you see from the outside, and what appears to be normal skin surrounding the biopsy site may indeed be involved with the skin cancer.
One of the biggest advantages of Mohs surgery is that it allows the surgeon to start very small and excise tissue conservatively around the scar left behind after your biopsy. If there is indeed tumor left, the Mohs surgeon will see this under the microscope and be able to track it – making sure to remove all of the tumor while removing as little of the normal tissue as possible. So take care of your newly diagnosed BCC or SCC sooner rather than later and avoid letting things get out of hand.