A Non-Healing Mixed Plaque on the Lateral Tongue in a Former Smoker
A 63-year-old retired schoolteacher is referred by his general practitioner for assessment of two oral mucosal lesions. He has a 45 pack-year smoking history, stopped four years ago, drinks arak at weekends, and takes amlodipine 5 mg daily for hypertension. On examination, the right lateral border of the tongue carries a 2.3 x 1.1 cm plaque with mixed white and erythematous areas extending towards the posterior third; it has been present for seven weeks and is mildly tender. The posterior margin feels firm on palpation. There is no cervical lymphadenopathy, and the floor of the mouth and tonsillar region are clear. Separately, the buccal mucosa shows bilateral, roughly symmetrical white striae with a faint erythematous border, present for about two years and burning when he eats tomatoes. Six years ago a white patch was excised from the left buccal mucosa and reported as hyperkeratosis with no dysplasia. He asks whether a mouthwash would settle both problems.
1. Rank the differential diagnosis for the tongue lesion and state, with reasoning, which lesion you would biopsy and why.
Read the worked answer
Ranking, highest concern first
- Oral squamous cell carcinoma or carcinoma in situ (erythroleukoplakia). Single, unilateral, non-homogeneous lesion; the lateral tongue is the highest-risk subsite; seven weeks' duration; a firm posterior margin suggesting induration; 45 pack-years plus alcohol. The red component matters - erythroplakia carries a far higher transformation rate than homogeneous leukoplakia.
- Chronic hyperplastic candidiasis. Possible, but does not explain the firmness; it must never be assumed, and a lesion persisting after antifungal treatment still needs biopsy.
- Lichenoid drug reaction. Amlodipine is a recognised cause, but drug lichenoid reactions are usually bilateral and this lesion is single.
- Traumatic keratosis. No sharp tooth, restoration or parafunctional habit identified.
- Proliferative verrucous leukoplakia. Would be expected to be multifocal and verrucous; this does not fit.
Which to biopsy The tongue lesion, without delay. It is the single, unilateral, non-homogeneous, indurated lesion in a high-risk subsite in a high-risk patient.
The buccal striae are bilateral, symmetrical and striae-predominant - the classic picture of oral lichen planus. Biopsy is not mandatory for typical bilateral disease, but becomes indicated if there is unilateral or asymmetrical change, erosion, ulceration, or any change on follow-up.
Key reasoning point: the two lesions are judged independently. A benign chronic condition does not lower the index of suspicion for the other, and the previous 'hyperkeratosis-only' report six years ago is evidence of field change, not reassurance.
2. Describe the biopsy you would perform, what you would send to the pathologist, and how you would manage a report of moderate dysplasia with clear margins.
Read the worked answer
Technique
- Incisional, not excisional: the lesion is over 2 cm, of uncertain nature and near the posterior tongue; an excision would be a cancer operation if it proves malignant.
- Sample the most suspicious area (the red, firm posterior margin) with a rim of clinically normal tissue, deep enough to include epithelium and lamina propria.
- Avoid diathermy or laser for the diagnostic specimen - thermal artefact compromises dysplasia grading.
- Orient the specimen on a card, place it in formalin, and use a separate pot for the buccal site if you sample it.
Information for the pathologist Site, size, duration, smoking and alcohol history, previous hyperkeratosis at another site, current medication including amlodipine, clinical photograph, and a specific request for dysplasia grading and a comment on the deep margin.
If moderate dysplasia with clear margins Dysplasia is a risk marker, not a cancer diagnosis. Transformation risk for moderate dysplasia is of the order of 10-15% over years, and clear margins do not guarantee clearance because of field change. Options, decided with the oral medicine / maxillofacial team: excision or laser ablation of the affected area, or a strict surveillance programme (review every three months for two years, then six-monthly, lifelong).
Either way: absolute smoking cessation, reduced alcohol, smoothing of sharp teeth or restorations, treatment of the symptomatic lichen planus with topical corticosteroid, and explicit documentation that follow-up is surveillance, not a guarantee. Recurrence or change means re-biopsy, never blind repeat sampling.
3. The patient asks you to 'just give a mouthwash and check again in six months'. How do you respond, and what do you document?
Read the worked answer
Explain the reasoning, not just the verdict. The lesion has been present seven weeks, sits on the lateral tongue, is mixed red and white, and feels firm. Those are the features that make cancer the main concern, and they are not features a mouthwash can address.
Why 'six months' is unsafe: a delay of months can allow a T1 lesion to become a T2 with nodal spread, changing treatment from a local excision to surgery plus neck dissection and radiotherapy. A chlorhexidine, antifungal or steroid rinse cannot exclude malignancy and may mask symptoms, and an antifungal is only reasonable if candidiasis is a genuine differential - and even then, persistence after two weeks mandates biopsy.
Offer something concrete instead of refusal: biopsy within days, an explanation of what it involves, the result timeline, and a two-week review for the buccal lichen planus (which can reasonably be treated with a topical corticosteroid while the tongue is investigated).
If he declines, this is informed refusal of a recommended investigation: explain and document the risk of delay in words he understands, offer a second opinion and a copy of the referral, write to his general practitioner, and record a review date of no more than two weeks rather than six months. The record should show what was said, not just 'patient refused'. Silence on the file is the position that becomes indefensible if the lesion is later malignant.