Oral lichen planus (“OLP”) is a chronic inflammatory condition affecting the mucous membranes of the oral cavity. Although typically benign and manageable, OLP carries a small but significant risk of malignant transformation into oral squamous cell carcinoma (“OSCC”). There are different pathways for oral cancers to develop, so this article will focus on OLP. For dentists and oral surgeons, understanding this condition is essential, particularly as negligence in diagnosis, monitoring, or referral may lead to tragic outcomes for patients.

What is oral lichen planus?

Lichen Planus is a chronic inflammatory autoimmune disease that affects skin, hair, nails, or mucous membranes. With OLP the body’s immune system attacks the mucous membranes in the mouth.¹ OLP lesions most commonly affect the gums, lips, inside of the cheek, and tongue.² They often present as bilateral, white, lacy lesions (known as Wickham’s striae) but may also appear as erythematous (red) or ulcerative lesions.

The cause of OLP is not fully understood, but it is associated with systemic autoimmune diseases, certain medications, and stress.³ OLP can be symptomatic, with patients reporting burning, pain, or sensitivity to spicy foods, or it can be asymptomatic and discovered during routine dental exams. And if a dentist is performing cancer screening exams, which are part of their regular practice and the standard of care, they should be able to recognize OLP and its potential for malignant transformation.

The importance of monitoring OLP

The goal of oral cancer screening is to detect potentially malignant lesions at their earliest stage. OSCC affects about 35,000 people in the US each year; 3% of cancers in males and 2% of cancers in females are OSCCs.⁴ OLP is more common in middle-aged adults, affecting women twice as often as men.⁵ It is most frequently diagnosed in people in their 50s, though it may occur at any age.⁶ While in the past there existed controversy about whether OLP transformed into oral cancer, it is currently understood that approximately 1% of patients develop OSCC.⁷ A failure to monitor OLP adequately can lead to a missed or delayed diagnosis of oral cancer. Dentists and other oral health professionals have a duty to not only recognize OLP but to follow it carefully and take appropriate action when concerning changes occur.

Dentists are responsible for periodically examining their patients’ faces, necks, and oral cavities thoroughly for the presence of lesions and diseases.⁸ The exam typically includes a personal, medical, and habit history and a physical examination that includes visual inspection and digital palpation to examine for abnormal enlargements of lymph nodes or salivary glands.⁹ Monitoring should be done more aggressively for high-risk patients, such as smokers, heavy alcohol users, or those with a history of cancer.

The importance of monitoring OLP stems from its potential to undergo malignant transformation. While the overall risk is relatively low, the potential consequences of progression to oral squamous cell carcinoma are serious. Malignant transformation is more commonly associated with the erosive or atrophic form of OLP, characterized by red lesions and painful ulcerations around the gums. Those patients that are symptomatic or exhibit non-healing ulcerations are at greater risk for developing OSCC.

Dentists must be vigilant for changes that may indicate malignant transformation. These include: color changes (e.g., from white to red or mixed red/white); a shift from a reticular pattern to erosive or ulcerative lesions; non-healing ulcerations; induration (thickening) of tissue; bleeding on palpation; increased pain or burning sensations; or rapid enlargement of the lesion. These clinical signs warrant immediate referral to an oral pathologist, oral surgeon, or otolaryngologist for further evaluation and biopsy. A dentist may be liable if they fail to identify the lesion, fail to attempt to diagnose the problem, or fail to refer the patient to a specialist.

How is lichen planus diagnosed?

The diagnosis of OLP is typically clinical, based on its characteristic appearance and distribution. However, because of its potential for malignant transformation and similarities to other oral pathologies, confirmation via biopsy is strongly recommended, particularly if the lesions are presenting with atypical, erosive, or ulcerative characteristics.

Once lichen planus is diagnosed, it is important for the dentist to monitor the conditions. Monitoring OLP involves regular documentation and clinical evaluation. Dentists should schedule regular follow-up visits (typically every 3 to 6 months), conduct thorough oral examinations, document lesion size, color, texture, and location with clinical notes and photographs, and educate the patient on symptoms to watch for.

A dentist regularly performing exams of the patient and practicing within the standard of care will perform a “brush” biopsy themselves or refer the patient to an oral surgeon to evaluate for a biopsy. The brush biopsy is simply that—a small brush is used to scrub the abnormal tissues, with the goal of accumulating cells on the brush for evaluation by a pathologist. A brush biopsy is noninvasive, does not require anesthetic, is easy to do, and is minimally uncomfortable for the patient. Positive results from a brush biopsy should lead to referral to an oral surgeon or ENT surgeon.

A surgeon will usually perform an excisional biopsy to surgically remove the lesion or a portion of it. If the tissue is positive for malignancy, the surgeon should remove the remaining tissue until there are negative margins.

Treatment for OLP focuses on reducing inflammation and providing relief of symptoms.¹⁰ There is no cure.

As the dentist tracks the patient, any significant changes in the lesions should prompt further investigation, including repeat biopsy. Significant changes include but are not limited to new ulcerations or new pain complaints.

When OLP changes to cancer

When evaluating a case for negligent delay of diagnosis of oral cancer from OLP, you must consider the types of changes to the OLP lesions, what was recorded about them, and what the provider did to address the changes. Did the dentist fail to refer the patient out, and/or fail to order any kind of diagnostic study such as imaging or a biopsy? Did the dentist continue to treat the patient despite the ongoing changes to the lesions? Tragically, malpractice may occur for the simple but all too common error of failing to follow up on a concerning biopsy report.

If a lesion exhibits disorganization indicative of OSCC, the oral surgeon will remove the abnormality to a depth and breadth sufficient to secure clean margins.

If a dentist fails to appropriately monitor OLP or delays referral when concerning signs are present, and the lesion progresses to OSCC, this may constitute negligence.

Surgical treatments for late-stage OSCC developed from OLP

The delay in diagnosing OSCC can be devastating for patients and their families. The longer the delay, the more extensive and invasive the surgical intervention needs to be. Common surgical treatments for advanced OSCC include:

• Wide local excision: Surgical removal of the tumor with a margin of healthy tissue. For larger lesions, such as removal of half of the patient’s tongue and adjacent lymph nodes, this may result in significant disfigurement or functional impairment.
• Neck dissection: Removal of lymph nodes in the neck if there is evidence of metastasis.
• Mandibulectomy or maxillectomy: Partial or complete removal of the jawbone if the cancer has invaded bone tissue.
• Reconstructive surgery: May be necessary to restore function and appearance, often involving free flaps or grafts. Tissues in the oral cavity, including the tongue, will be reconstructed, to an extent, through a forearm flap surgery. In such a surgery a portion of skin from the patient’s forearm is removed, flipped inside out, and sutured to the remaining structures in the patient’s mouth. The patient will commonly develop permanent speech dysfunction, permanent swallow dysfunction, eating impairment (unable to move food around without tongue), and reduced ability to enjoy food.¹¹Patients will often have to have some, if not all, of their teeth removed for treatment.
• Adjuvant therapy: Radiation and/or chemotherapy are often required post-surgery, which have its own risk of complications, including lymphedema.

These treatments are not only physically and emotionally taxing but can also carry substantial financial costs, cause lost wages, and, of course, diminished quality of life.

Conclusion

Oral lichen planus, while often benign, carries a real risk of malignant transformation. Cases involving OLP demand careful analysis of dental records, biopsy history, follow-up patterns, and patient communication. Establishing a failure to monitor or respond to concerning changes can form the basis of a compelling claim, especially when late-stage oral cancer is the outcome.

A version of this article was published in the May 2025 issue of Trial News.

¹“Oral Lichen planus.” mayoclinic.org, December 24, 2024. www.mayoclinic.org/diseases-conditions/oral-lichen-planus/symptoms-causes/syc-20350869. 

²Id. 

³Id. 

⁴Siegel, Rebecca L., Ann G. Giaquinto, and Ahmedin Jemal. “Cancer statistics, 2024.” CA: A Cancer Journal for Clinicians, vol. 74., no. 1, 2024, pp 12-49. Wiley, doi:10.3322/caac.21820. 

⁵Raj, Grace, and Mary Raj. “Oral Lichen Planus.” StatPearls, StatPearls Publishing, 6 Feb. 2023, www.ncbi.nlm.nih.gov/books/NBK578201/. 

⁶Id. 

⁷Aghbari, S. M. H., A. I. Abushouk, A. Attia, et al. “Malignant Transformation of Oral Lichen Planus and Oral Lichenoid Lesions: A Meta-analysis of 24 Studies.” Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology, vol. 123, no. 5, 2017, pp. 547–560. Again, some controversy exists, as at least one paper reports as many as 12.5% of patients experience malignant transformation, see Raj, Grace, “Oral Lichen Planus,” https://www.ncbi.nlm.nih.gov/books/NBK578201/. 

⁸Lingen, Mark W., et al. “Evidence-Based Clinical Practice Guideline for the Evaluation of Potentially Malignant Disorders in the Oral Cavity.” The Journal of the American Dental Association, vol. 148, no. 10, Oct. 2017, pp. 712–727. 

⁹Lingen, Mark W., et al. “Evidence-Based Clinical Practice Guideline for the Evaluation of Potentially Malignant Disorders in the Oral Cavity: A Re-port of the American Dental Association.” Journal of the American Dental Association, vol. 148, no. 10, Oct. 2017, pp. 712–727.e10. 

¹⁰Raj, Grace, and Mary Raj. “Oral Lichen Planus.” StatPearls, StatPearls Publishing, 6 Feb. 2023, www.ncbi.nlm.nih.gov/books/NBK578201/. 

¹¹Skin on your forearm does not, after all, have tastebuds.