Conway McLean, DPM, Journal columnist

Most humans develop various spots, bumps, and lesions over the years. A recent patient, let’s call her Sara, had noticed a spot on her lower leg one morning, during her shower ritual. She had no history of skin “problems” and no memory of any particularly bad sunburns (although we all know how fallible memories are). It didn’t look like much, since it wasn’t terribly dark, irregular, or rough. She thought little of it.

During an exam with her podiatrist (for an unrelated problem), she was informed that spot looked a little suspicious. Not terrible, not bizarre, but a little “off.” A biopsy was recommended, which is a surgical procedure, and that’s scary. It was phrased in such a way that the biopsy was not a necessity but a very good idea, since it did look odd. In summary, what you don’t know can hurt you, at least when it comes to strange spots on the skin. Sara went ahead and gave her consent to have the procedure.

In retrospect, it hardly qualified as surgery. She felt a blast of something extremely cold and a slight pressure. The area was mildly sore the next day. Other than that, it was a simple process. Much to her surprise, upon returning to the office for follow-up, she was informed the lesion biopsied was a deadly form of skin cancer, a malignant melanoma. This was hardly the news she was expecting.

Malignant melanoma is the deadliest form of skin cancer, although thankfully it is not the most common. Malignancies of the skin are the most common form of cancer in general but, thankfully, only about 1% of these are MM. Still, as the name suggests, it is the deadliest with 8,000 deaths occurring already in 2023 nationally. More people are surviving this disease now because of early identification.

Our patient, Sara, was naturally alarmed. This form of skin cancer can kill you; could hers have such an unpleasant result? “How to know?” was her first question at hearing the potentially deadly diagnosis. The other more common types of skin cancer, basal cell and squamous cell (both terms referring to the layer of skin they affect) are more likely to spread locally, meaning the lesion grows larger. MM, in contrast, is more likely to send malignant cells to lymph nodes, either nearby or farther away.

This is where Clark and Breslow come into the conversation. Both terms refer to systems measuring depth, how far into the body the skin tumor has grown. With MM, there’s a clear relationship, the deeper the melanoma has grown, the deadlier it is. Hers was identified early enough that her chances of survival were quite good.

In a level 1 lesion, it is confined to the epidermis, the outermost skin layer. In a level 2, the tumor has invaded the next layer of our skin (the papillary dermis). Level 3, and higher levels, have grown into progressively deeper layers of the body. This is the Clark’s Staging system. In contrast, the Breslow system goes by actual measurements (in millimeters, naturally). Again, the higher the number, the greater the penetration and the worse the prognosis.

Some skin conditions are easily identified by visual inspection. But discolored spots, roughly circular areas of abnormal coloration, these often are more challenging, even for experts. For years, it has been obvious that simply looking closely at a lesion, even with magnification, is very inaccurate. The appearance of a skin cancer can and does vary greatly. Certainly, some changes should raise the alarm. For example, when a spot of skin has different colors. Another is the development of varied textures or some prominence. Typically mentioned is one that’s changing or is visibly irregular in contour.

The clear and obvious next step is a biopsy. Everyone has their favorite technique but, somehow, tissue must be obtained. A punch biopsy, using a sharp-edged tube, is one of the favorites of clinicians and pathologists alike (a physician specializing in tissue identification). Tests allow us to identify cancerous cells with great accuracy. A biopsy, the procurement of a specimen from some structure, is a practice considered the standard of care for many decades.

Many skin lesions are treated with cryotherapy, in which intense cold is applied to a lesion, literally freezing it to death. The downside is the lack of identification: you never know what the problem was. Tissue treated in this manner cannot be identified.

Skin cancers sometimes look “typical,” but this is by no means dependable. They may be completely benign appearing, or textbook classic. A definitive determination of the type of lesion, what it is and why it is, are possible only with the study of some representative cells. And an observant physician, especially one dealing with the foot, ankle, and lower leg, should be looking for these lesions. (After all, few of us reliably put sunblock on our feet.)

Strange spots and bumps develop on the foot and lower leg, for a host of reasons. Some of them are inconsequential, generally incapable of causing harm, and others where this is not the case. If your doctor identifies a lesion that is abnormal in some way, have it biopsied. These are “band-aid” procedures, entailing minimal risk. And for some, the benefits of a simple skin biopsy can be tremendous, some would say lifesaving.

EDITORS NOTE: Dr. Conway McLean is a podiatric physician now practicing foot and ankle medicine in the Upper Peninsula, having assumed the practice of Dr. Ken Tabor. McLean has lectured internationally on surgery and wound care, and is board certified in both, with a sub-specialty in foot orthotic therapy. Dr. McLean welcomes questions, comments and suggestions at drcmclean@penmed.com.