What are the recommended steps for a patient with a slowly growing brown lesion on their tongue over 18 years?

Urgent Biopsy Required for This High-Risk Lesion

Any brown or pigmented lesion on the lateral tongue that has been present for 18 years requires immediate incisional biopsy within 2 weeks to exclude malignancy, regardless of the slow growth pattern. 1

Why This Lesion is High-Risk

The lateral tongue is one of the highest-risk anatomic sites for oral squamous cell carcinoma and malignant transformation of leukoplakia. 1, 2 The 18-year duration does not provide reassurance—oral leukoplakia and early malignancies can remain stable for years before transforming. 2

Critical point: Non-homogeneous leukoplakia (which includes pigmented or brown lesions with color variation) carries significantly higher malignant transformation risk than homogeneous white plaques, with 5-year cancer-free survival dropping from 90.5% to 59.0% for high-grade dysplasia. 2

Immediate Diagnostic Steps

Mandatory Actions Before Any Treatment

• Perform incisional biopsy of the lesion within 2 weeks, taking tissue from the most suspicious area (darkest pigmentation, any raised or irregular borders). 3, 1

• Document the exact size, location, and obtain photographic evidence before biopsy. 1

• Do not attempt empiric treatment or observation—the lateral tongue location and long duration mandate tissue diagnosis. 1

Pre-Biopsy Laboratory Evaluation

• Obtain full blood count to rule out hematologic disorders (leukemia, anemia). 3

• Check coagulation studies to ensure no surgical contraindications. 3

• Measure fasting blood glucose, as hyperglycemia predisposes to invasive fungal infections that can mimic malignancy. 3

Differential Diagnosis to Consider

The brown pigmentation on the lateral tongue could represent:

• Oral leukoplakia with dysplasia (most concerning given location and duration) 1, 2

• Early squamous cell carcinoma (lateral tongue is a high-risk site) 1, 2

• Melanotic macule or oral melanoma (rare but must be excluded with biopsy) 4

• Amalgam tattoo (if patient has dental restorations nearby, but still requires biopsy confirmation) 4

Post-Biopsy Management Algorithm

If Biopsy Shows High-Grade Dysplasia or Carcinoma

• Immediate referral to oral and maxillofacial surgery or head and neck surgery for definitive excision. 1

• Malignant transformation risk is highest in the first 2-3 years after diagnosis of high-grade dysplasia. 2

If Biopsy Shows Low-Grade Dysplasia or Benign Hyperkeratosis

• Consider ALA-PDT (aminolevulinic acid photodynamic therapy) as first-line treatment, which achieves complete response in 16.49-88.89% of cases. 5

• Alternative: CO2 laser ablation, though this causes more scarring than PDT. 5

• Mandatory tobacco and alcohol cessation counseling, as 75% of oral cancers are attributable to these exposures. 5

ALA-PDT Protocol (If Appropriate After Biopsy)

• Verify no contraindications: porphyria, coagulopathy, pregnancy, uncontrolled systemic disease. 5

• Apply 20% ALA solution to lesion extending 3-5 mm beyond margins, cover with film, incubate 2-3 hours. 5

• Irradiate with 630 nm laser at 100 mW/cm² in 3-minute sessions alternating with 3-minute rest until total dose reaches 100 J/cm². 5

• Critical: Patient must avoid all light exposure to treated area for minimum 48 hours post-treatment. 5

• Repeat treatment every 2-3 weeks based on healing response. 5

Common Pitfalls to Avoid

• Never assume a lateral tongue lesion is benign without histologic confirmation—this is a high-risk site for oral squamous cell carcinoma. 1

• Do not delay biopsy for empiric antifungal treatment—if the lesion cannot be scraped off, it is not candidiasis. 1

• Do not rely on clinical appearance alone to distinguish between leukoplakia, lichen planus, and early malignancy. 1

• Failing to enforce strict light avoidance for 48+ hours post-PDT compromises outcomes if PDT is eventually used. 5

Long-Term Surveillance After Treatment

• Sequential biopsies every 6-12 months are indicated for high-risk patients (age >60, lateral tongue location, non-homogeneous lesions). 2

• Multiple biopsies correlate with early detection of malignant transformation in high-risk populations. 2

• Continued tobacco cessation is essential for preventing recurrence and new lesions. 5