When Should You Consider Biopsying a Dark Spot Inside Your Mouth?

"If you notice a new spot that’s growing, has an irregular shape, or just won’t go away, it’s a good idea to have it looked at."

Maybe you or your dentist or dental hygienist noticed a dark spot inside your mouth - tongue, inner cheeks, lips, roof of the mouth, etc., and think it needs to be further evaluated. While many pigmented spots like amalgam tattoos (near areas of older silver fillings) or harmless melanotic macules (small, benign, non-raised, dark patches) are perfectly safe, some dark spots could signal a more serious problem. I hope to clarify some doubts about when to get a dark spot biopsied.

One helpful way we explain this to patients is by using the ABCDE rule, originally made for skin melanoma but also useful for oral spots:

• Asymmetry: One side looks different from the other.

• Border: Edges are uneven or jagged

• Color: Spot has multiple colors or uneven shading

• Diameter: Larger than 6 to 7 millimeters (about the size of a pencil eraser)

• Evolving: Changing in size, shape, or symptoms over time

So if you notice a new spot that’s growing, has an irregular shape, or just won’t go away, it’s a good idea to have it looked at. A dark spot which checks off one or more of these boxes may warrant a biopsy to rule out conditions like oral melanoma or other concerns [1,2].

Biopsies are straightforward, low-risk procedures that we do right here in the office. Depending on the lesion, we first numb the area and then take a small punch or scalpel sample. The sample gets sent to an oral pathologist to study the underlying tissue. Catching something early is key for peace of mind and determining if any further action needs to be taken, since oral melanomas are rare but can be aggressive if missed [3].

If you or your dentist spots a dark patch that looks unusual or just doesn’t feel right, don’t wait to get it checked. At Oral Medicine of Wisconsin, we focus on evaluating these lesions carefully and guiding you on whether a biopsy is the right step.

References

[1] Alawi F. Pigmented lesions of the oral cavity: an update. Dent Clin North Am. 2020;64(2):387-403.

[2] Villa A, Marcarini L, Strohmenger L, Abati S. Melanoma of the oral cavity: a challenge for early diagnosis. Int J Dent Hyg. 2018;16(4):e117-e123.

[3] Udeabor SE, Rana M, Wegener G, Gellrich NC, Eckardt AM. Oral malignant melanoma: a review of 25 cases in a single institution. J Cranio-Maxillofac Surg. 2019;47(10):1582-1586.