Skin Cancer Differential Diagnoses: Things That Aren’t Skin Cancer

Skin Cancer Differential Diagnoses

By Ruth Werner, BCTMB

I recently finished an ABMP three-fer: a 90-minute course, a feature article, and a column—all on the topic of skin cancer. (Be sure to check them out, I am very proud of these projects!) 

But basal cell carcinoma, cutaneous squamous cell carcinoma, and melanoma are not the only things that can cause suspicious-looking skin changes. And because we see more of our clients’ skin than they do, it is useful to be able to know what skin cancer looks like and recognize situations that might prompt some careful questions. That way, when we ask, “Tell me about this raised dark area on your back,” and they say, “Oh my doctor told me it’s just a seborrheic keratosis,” we’ll have a clue what they’re talking about.

So, here’s a short list of things that might make us think of skin cancer, but they’re not skin cancer.


Freckles are typically small, flat spots where extra melanin accumulates. Melanin, of course, is a type of pigment we produce that adds color to our skin. It serves an important purpose: it deflects UV radiation to offer some protection from the damaging effects of sunlight. Exposure to sunshine tends to make these spots more active, so freckles sometimes appear to come and go, depending on the season and outdoor activities.

We often associate freckles with light-skinned blondes and redheads, but people with all kinds of skin tones can have freckles.


Blue nevi moleMoles are similar to freckles, but they have some important differences. They don’t come and go with sun exposure, and while freckles are flat, moles may be raised and have a different texture compared to nearby skin.

Moles are often brown or black, but sometimes they are reddish or purple. There’s even a type called blue nevi (nevus is the singular technical term for mole).

Moles have the potential to be an early site of melanoma development, but most melanomas don’t start here. That said, some moles, especially blue nevi, can hide the changes in cell growth that mark cancer, so any evolution in the size, texture, or other signals like itching or bleeding within or around a mole definitely call for attention from a dermatologist.

(Pictured: Blue nevi mole)


SunspotsA sunspot (also called a lentigo or actinic lentigo), is a flat, slightly darker area that appears in older people, usually on the face or other areas that are sun-exposed, like the hands. They may be small, like in this photograph, or quite large. They are usually symmetrical: round or oval.

 By contrast, lentiginous melanoma looks like sunspots, but usually has a notched, uneven edge as a distinguishing feature.

(Pictured: Sunspots)


Seborrheic Keratosis

Seborrheic KeratosisSeborrheic keratoses look like dark, pasted-on warty growths. They are raised, and they have a rumpled texture. They don’t hurt, unless they get caught on clothing. They can look alarming—like melanoma, but their borders are very distinct. Of course the arbiter of this judgment is not a massage therapist, but a doctor.


(Pictured: Seborrheic keratoses)



Closeup of a seborrheic keratoses lesion


These lesions are not dangerous, they don’t spread like a rash, and they’re not contagious, but if a lot of them are present, they might disrupt the flow of massage, as might happen for this person in this image.

(Pictured: A closeup of a seborrheic keratoses lesion)


LipomasLipomas are fatty tumors, usually in the superficial fascia. These can occur anywhere, on the trunk, right over the spine, and on the extremities as we see in this photograph.

Lipomas aren’t dangerous, but this is a situation where we need to be especially careful about our language. If we say, “oh look at your fatty tumor,” it’s not hard for someone to hear “you have cancer”—even if we use the term lipoma, people may misinterpret that in an alarming way.

And that’s a short list of benign skin markings that might make us think about skin cancer. We must still refer undiagnosed skin issues—especially ones that we observe are new or changing—out for a more formal diagnosis. Aren’t you glad it’s not your call to determine if a seborrheic keratosis is malignant or not?

(Pictured: Lipomas)


In partnership with our clients, massage therapists are on the front lines of skin defense and health maintenance. That’s a great place to be helpful.

For more on skin cancer, and on how to carefully bring our clients’ attention to potential problems while not being alarmist or stepping outside our scope of practice, please see the feature article, “Skin Cancer: A Closer Look” in the March/April 2023 edition of Massage & Bodywork magazine. 

author bio

Ruth Werner is a former massage therapist, a writer, and an NCBTMB-approved continuing education provider. She wrote A Massage Therapist’s Guide to Pathology (available at, now in its seventh edition, which is used in massage schools worldwide. Werner is available at    

Related Content:

• “Skin Cancer: A Closer Look” by Ruth Werner

• “Skin Cancer and Skin of Color” by Ruth Werner 

• Course: “Skin Cancer: Beyond the Basics” with Ruth Werner 



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