Is a biopsy necessary for oral lichen planus and what does it typically show?

Biopsy for Oral Lichen Planus: Necessity and Histopathological Findings

A biopsy is not always necessary for oral lichen planus when clinical features are typical, but it is essential when there are atypical features, diagnostic uncertainty, or suspicion of malignant transformation. 1

When to Perform a Biopsy

Biopsy is indicated in the following situations:

• Atypical clinical presentation or diagnostic uncertainty
• Suspicion of malignant transformation (persistent areas of hyperkeratosis, erosion, erythema, or new warty/papular lesions)
• Failure to respond to adequate treatment
• Before initiating second-line therapy
• Pigmented areas to exclude abnormal melanocytic proliferation

While oral lichen planus is often diagnosed clinically, histopathological confirmation provides definitive diagnosis and helps rule out other conditions with similar appearance, particularly those with malignant potential 2.

Histopathological Findings in Oral Lichen Planus

When performed, a biopsy of oral lichen planus typically shows:

• Hyperkeratosis of the epithelium
• Hydropic degeneration of the basal cell layer
• Band-like lymphocytic infiltrate beneath the epithelium
• Atrophic epidermis with loss of rete pegs
• Homogenization of collagen in the upper dermis
• Apoptosis of keratinocytes (Civatte bodies)

The biopsy should be taken from the most active area of the lesion to ensure representative findings 2.

Diagnostic Process

The diagnostic process for oral lichen planus requires:

1. Clinical examination: Identifying characteristic reticular, erosive, bullous, or plaque-like lesions
2. Biopsy: For histopathological confirmation when indicated
3. Direct immunofluorescence (DIF): May be needed in cases where the diagnosis remains uncertain after routine histopathology
4. Clinical follow-up: Essential after initial biopsy as OLP mimics can manifest, sometimes requiring additional biopsies 1, 3

Malignant Potential

The World Health Organization classifies oral lichen planus as a potentially malignant disorder, with risk of oral squamous cell carcinoma developing in up to 2% of lesions 3. This underscores the importance of proper diagnosis and regular monitoring.

Practical Considerations for Clinicians

• When submitting biopsy material, provide specific information to pathologists including clinical appearance, distribution, and patient history
• Ensure good clinicopathological correlation in the diagnostic process
• Consider that oral lesions of lichen planus are chronic, rarely undergo spontaneous remission, and are often a source of morbidity 4
• Regular follow-up is essential due to the chronic nature of the disease and its potential for malignant transformation

Diagnostic Challenges

Accurate identification of oral lichen planus can be challenging because:

• It has diverse forms of presentation
• There are important differential diagnoses to consider
• It shares features with other mucosal disorders
• The risk of malignant change necessitates careful evaluation 5, 6

By understanding when a biopsy is necessary and what histopathological findings to expect, clinicians can better manage patients with oral lichen planus and monitor for potential complications.