“Oh, it’s just a canker sore; it’ll go away on its own.” This is a phrase we utter and hear almost daily in our clinics. And, for the most part, it’s often true. Aphthous ulcers are among the most common oral lesions we encounter, typically benign, and they usually vanish within a week to ten days.
However… in a small but critical percentage of cases, that ulcer isn’t “just simple” at all. It can be an early warning sign of a much more serious underlying condition, potentially representing your only window to detect it early. The real dilemma is that an early-stage malignant ulcer can look remarkably similar to a common one, and that’s precisely the trap any dentist could unknowingly fall into.
This is exactly why every dental professional must cultivate a “sixth sense” or an internal alarm bell that rings when faced with certain ulcers. In this article, we’ll explore together when an “innocent” ulcer transforms into a “potential suspect,” and when you simply must make the decisive call to perform a biopsy.
The Alarm Bell: When Should You Be Suspicious of an Oral Ulcer?
Not all ulcers are created equal. There are specific “red flags” that, if observed, demand you pause and reconsider your initial assessment. The fundamental rule states: Any oral ulcer that fails to heal within two weeks should be considered malignant until proven otherwise (1).
But there’s more to it than just the two-week rule. You absolutely need to lean towards an earlier biopsy decision if the ulcer exhibits any of the following characteristics:
1. The “High-Risk” Locations
Not every area in the mouth carries the same level of risk. Certain regions are classified as “high-risk sites” because the vast majority of oral squamous cell carcinomas originate there. If you spot an ulcer in these specific locations, your concern should immediately escalate:
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Lateral Border of the Tongue: Especially its posterior third. This is, by far, the most dangerous and common site.
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Floor of the Mouth: The area directly beneath the tongue.
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Retromolar Area: The region behind the last molar.
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Ventral Surface of the Tongue: The underside of the tongue.
2. The Ulcer’s Appearance Itself
A typical, benign ulcer usually presents with pain, regular, reddish borders, and a yellowish base. However, an ulcer that should raise your suspicions often looks quite different:
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Painless: Many malignant ulcers, in their early stages, don’t cause pain. This often leads to patient delay in seeking care.
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Indurated, Everted Borders: Its edges feel hard and appear rolled outwards.
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Indurated Base: The base of the ulcer feels firm to the touch.
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Bleeds Easily on Palpation: It tends to bleed readily when you gently touch or examine it.
3. Failure to Respond to Treatment
Imagine a patient presents with an ulcer you’ve initially diagnosed as benign, for which you’ve prescribed conservative treatment, perhaps an antiseptic mouthwash and analgesics. If they return a week later saying, “Doctor, it’s still exactly the same,” this is where your internal alarm must sound loudly.
The Rule: Any ulcer that persists and shows no improvement after 7-10 days, particularly after removing any potential local irritant (like a sharp tooth or restoration edge), warrants serious consideration for a biopsy.
Before the Scalpel: Auxiliary Examinations
Before you definitively decide on a biopsy, there’s a crucial step you might consider, especially if your suspicion level is already high.
The Smart Move: Refer the patient for a neck and floor of the mouth ultrasound. The primary goal of this imaging is to thoroughly assess the status of the regional lymph nodes. If you detect any abnormal enlargement in these nodes, it significantly amplifies the suspicion that the ulcer is indeed more than just a simple inflammation (2).
The Art of Biopsy: Performing an Incisional Biopsy Correctly
A biopsy isn’t just about “cutting out a piece of tissue.” It’s a procedure governed by specific principles and rules. If not performed correctly, the sample might prove inadequate for an accurate diagnosis.
When there’s a strong suspicion of malignancy, the preferred type of biopsy is an Incisional Biopsy. This means you take only a portion of the ulcer, rather than attempting to remove the entire lesion.
Proper Steps for an Incisional Biopsy:
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The Shape: Your biopsy specimen should ideally be taken in a “wedge” or “triangular” shape. More crucial than the shape, however, is the depth; the biopsy must be sufficiently deep.
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The Site: This is perhaps the most critical point. Never take the biopsy solely from the center of the ulcer. The center is often composed of necrotic tissue, which will likely yield no diagnostic information.
The Correct Approach: Your wedge-shaped specimen must include a portion of the active border of the ulcer and a segment of the adjacent normal-appearing tissue. The sample absolutely needs to contain both (3).
Why include normal tissue? So the histopathologist can directly compare the morphology of the healthy tissue with the diseased tissue within the very same specimen. This comparative analysis is what allows for a precise diagnosis of the condition.
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Fixation and Transport: Immediately upon taking the specimen, place it into a container filled with 10% formalin solution. Do not allow it to dry out. Label the container clearly with the patient’s full details.
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The Biopsy Report: When submitting the specimen to the lab, you must include a detailed accompanying report containing:
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Full patient personal data.
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Relevant medical history (e.g., smoking, alcohol consumption).
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A precise ulcer description.
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Your provisional diagnosis.
This comprehensive information significantly assists the pathologist in reaching the correct diagnosis.
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The Bottom Line: Delay Is the Greatest Enemy
Doctor, when it comes to suspicious oral ulcers, time is absolutely not on our side. Relying on simple analgesics and mouthwashes for extended periods without a definitive diagnosis can tragically lead to disease progression and make subsequent treatment far more challenging.
Your role as a dentist extends beyond treating cavities and gum disease; you are, in fact, the first line of defense in the early detection of oral cancer. Always remain vigilant, and never, ever hesitate to make the decision to perform a biopsy or refer the patient to an oral and maxillofacial surgeon if you harbor even a 1% suspicion. That single decision could very well be the one that saves your patient’s life.
