A persistent white patch on the lateral tongue
A 48-year-old woman is referred with a 1.8 cm white, non-removable plaque on the right lateral tongue present for 6 months. She is a non-smoker and drinks little alcohol. She has no pain, no ulceration and no cervical lymphadenopathy. She has a history of oral lichen planus diagnosed 5 years ago, with bilateral buccal striae. The white patch is well demarcated, slightly elevated and has a granular surface; it does not wipe off. A previous dentist told her it was "just lichen planus" and no biopsy was taken. She is anxious about cancer because her father had oral cancer.
1. How would you distinguish between oral lichen planus, a lichenoid lesion and leukoplakia clinically, and why does the distinction matter here?
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Clinical distinction:
- Oral lichen planus (OLP): typically bilateral, symmetrical, reticular striae (Wickham striae), often on buccal mucosa; may have erosive/atrophic areas. Lesions are usually multiple and symmetrical.
- Lichenoid lesion: similar appearance but often unilateral, related to a drug or restoration (e.g., amalgam), and may resolve on removal of the cause.
- Leukoplakia: a white patch that cannot be characterised clinically or pathologically as any other disease; it is a diagnosis of exclusion. A solitary, unilateral, well-demarcated plaque on the lateral tongue in a patient with no obvious cause is leukoplakia until proven otherwise.
Why it matters: OLP has a small malignant transformation risk, but a solitary, non-homogeneous leukoplakia on the lateral tongue has a substantially higher risk of dysplasia or carcinoma. The previous label of "just lichen planus" may have delayed diagnosis. The lesion's unilaterality, granular surface and persistence for 6 months are red flags that mandate biopsy. The history of OLP does not exclude a new, separate leukoplakia or carcinoma.
2. What is the appropriate biopsy strategy, and how would you interpret a histopathology report showing mild dysplasia?
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Biopsy strategy:
- Perform an incisional biopsy of the most suspicious area (the granular, elevated part), including the interface with normal tissue and adequate depth (including submucosa).
- Multiple biopsies may be needed if the lesion is heterogeneous, because dysplasia can be focal and a single sample may miss a more advanced area.
- Send in formalin with clinical details; request comment on epithelial dysplasia, architecture and margin status.
Interpreting "mild dysplasia":
- Mild dysplasia (low-grade) involves architectural and cytological atypia confined largely to the basal/lower third.
- It is not benign, but the risk of progression is lower than with moderate/severe dysplasia or carcinoma in situ.
- Management is complete excision (or close follow-up with re-biopsy) rather than reassurance alone, because dysplasia is a risk factor and sampling can underestimate severity.
- The patient should be counselled about the need for excision, review and cessation of any risk factors, and warned that recurrence is possible.
3. The excised specimen shows mild to moderate dysplasia with clear margins. What follow-up would you recommend, and what would trigger re-biopsy?
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Follow-up:
- Review at 3 months, then 6-monthly for at least 2 years, then annually; the frequency should reflect the degree of dysplasia and the patient's anxiety and risk factors.
- Examine the whole oral mucosa at each visit, not just the excision site, because field change means new lesions can appear elsewhere.
- Encourage smoking and alcohol cessation (even though she is a non-smoker, alcohol reduction is relevant) and good oral hygiene.
Triggers for re-biopsy:
- Any new or recurrent white or red patch, ulceration, induration, or change in surface texture.
- Any lesion that persists beyond 2–3 weeks after removal of an identifiable cause.
- New symptoms such as pain, bleeding, or otalgia.
- Any cervical lymphadenopathy.
The key principle is that a patient with a dysplastic lesion remains at increased risk and needs long-term surveillance, not a single "all clear" after excision.