Challenges in the diagnosis of oral lichenoid lesions: a clinical case report

Desafios no diagnóstico de lesão liquenoide oral: relato de caso clínico

ABSTRACT

The term oral lichenoid lesion is used to characterize a group of lesions which present clinical and histological characteristics similar to oral lichen planus, but that have a recognizable causal factor, the removal of which can lead to regression of the lesions. Histologically, both lesions reveal a band-shaped lymphohistiocytic infiltrate arranged subepithelially. By comparison to oral lichen planus, oral lichenoid lesion may be associated with exogenous agents, such as restorative dental materials and medications, and presents a greater risk of malignant transformation. Although similar, the lesions require different approaches. A correct distinction between them is necessary to determine the appropriate treatment and long-term monitoring. This case report presents the case of a 64-year-old male patient with a history of smoking, who presented a unilateral leukoplakic lesion in the buccal mucosa region, and discusses difficulties typically encountered in correct diagnosis of oral lichenoid lesion. The lesion was diagnosed as oral lichenoid lesion. The patient was treated, with follow-up for 15 months, and with no signs of recurrence.

Indexing terms
Diagnosis, differential; Diagnosis, oral; Pathology, oral

RESUMO

O termo lesã o liquenoide oral é usado para caracterizar um grupo de lesões que apresentam características semelhantes ao líquen plano oral, clínicas e histológicas, mas que apresentam um fator causal reconhecível, cuja remoção pode levar à regressão das lesões. Ambas as lesões revelam, histologicamente, um infiltrado linfo-histiocítico em forma de banda e disposto subepitelialmente. A lesão liquenoide oral pode estar associada a agentes exógenos, como materiais restauradores odontológicos e medicamentos, e apresenta um risco maior de transformação maligna em comparação ao líquen plano oral. Mesmo que semelhantes, essas duas lesões necessitam de abordagens diferentes, sendo necessário uma correta distinção entre elas para determinar o tratamento adequado e o monitoramento a longo prazo. Esse relato de caso tem como objetivo apresentar o caso de um paciente de 64 anos de idade, sexo masculino, com histórico de tabagismo, que apresentava uma lesão leucoplásica unilateral em região de mucosa jugal e discutir a respeito da dificuldade encontrada para se diagnosticar corretamente casos de lesão liquenoide oral. A lesão recebeu o diagnóstico final de lesão liquenoide oral, e o paciente foi tratado, permanecendo em acompanhamento por 1 ano e 3 meses, sem sinais de recidiva.

Termos de indexação
Diagnóstico diferencial; Diagnóstico bucal; Patologia bucal

INTRODUCTION

Oral Lichenoid Lesion (OLL) is a generic term used to describe a group of lesions in which the clinical or histological presentation is compatible with Oral Lichen Planus (OLP). However, OLL presents a recognizable causal factor, which upon elimination or resolution may lead to disappearance of the lesion [¹,²]. Although there are still no universally accepted clinicopathological criteria, OLLs include lesions caused by reaction to exogenous substances and other immune-mediated conditions, such as oral graft-versus-host disease [³].

Histologically, both OLP and OLL are characterized by Oral Lichenoid Mucositis (OLM): a band-like infiltrate of lymphohistiocytic inflammatory cells at the epithelial-connective tissue interface [¹,⁴]. Degeneration of the basal layer and migration of inflammatory cells into the epithelium are common histological features of OLM [⁵]. Cases of OLL, may present epithelial dysplasia, called “lichenoid dysplasia” whose risk of malignancy is low (<3%) [⁴]. The prognosis of OLM depends on the subtype in question, with OLL presenting a statistically higher risk of malignant transformation than OLP [¹,⁴].

Considering that the pathophysiology and treatment of OLP and OLL are different, precise distinction between them is important [⁶]. This study reports a case of OLL and discusses its challenging diagnosis.

CASE REPORT

A 64-year-old male patient was referred to a dental clinic due to a history of leukoplakia in the buccal mucosa. The patient’s clinical history presented no systemic abnormalities, and he reported having been a smoker for approximately 30 years. Intraoral examination revealed a 3-mm plaque-shaped lesion in the left buccal mucosa, leukoplakia in color, fibrous consistency, rough surface, and unknown duration of evolution (figure 1). Based on the clinical evaluation, the diagnostic hypothesis was leukoplakia. An excisional biopsy was performed and the specimen was sent for histopathological analysis.

Figure 1
Intraoral clinical aspect showing the presence of leukoplakic lesion in the left buccal mucosa region.

The histopathological analysis revealed a fragment of oral mucosa covered by parakeratinized stratified squamous epithelium. In the underlying connective tissue, a dense band-like lymphocytic infiltrate was observed in the subepithelial region. Taken together with the clinician’s information, we arrived at a histopathological diagnosis of OLL (figure 2). The patient is being monitored without signs of recurrence (figure 3).

Figure 2
Histopathological examination showing the presence of intense lymphocytic inflammatory infiltrate arranged in a band and located subepithelially.

Figure 3
Intraoral aspect showing absence of recurrence 1 year and 3 months after the surgical approach.

DISCUSSION

Accurately classifying inflammatory processes with lichenoid features in the oral mucosa remains a diagnostic challenge [⁶]. OLM refers to a group of mucosal lesions-including OLP and OLL. It is characterized by a chronic lymphocytic inflammatory infiltrate with a band-like subepithelial distribution in the lamina propria. This pattern is often accompanied by liquefactive degeneration of the basal cells in the oral epithelium [¹]. Histologically, OLP and OLL are indistinguishable. In this context, a comprehensive clinicopathological diagnostic approach is essential for all cases presenting with white lesions of the oral mucosa, in order to establish a complete and accurate diagnosis of OLP or OLL, and to ensure appropriate, case-specific follow-up and monitoring [⁴].

OLP is a chronic mucocutaneous inflammatory disease mediated by T cells [⁴]. It is the most common subtype of OLM, and is clinically characterized by multiple, leukoplakic lesions, arranged bilaterally and, in many cases, symmetrical [⁴,⁷]. OLL is less common, and is characterized by unilateral, single, and asymmetrical leukoplakic lesions, and there may be a “recognizable causal factor”. Elimination or resolution of such factors generally results in disappearance of the lesion [⁴]. OLL may be associated with allergenic agents, such as restorative materials, systemic medications, or even foods [⁸]. When associated with medications, OLL is often triggered by rheumatic anti-inflammatory drugs, antihypertensives, antidiabetics, anticonvulsants, and immunomodulatory drugs [⁹].

The most common etiology of OLL is amalgam restorations, where toxic metals present in this restorative material can lead to mucocutaneous inflammatory reactions and, in general, may produce manifestations of chronic irritation of slow contact hypersensitivity [⁸,¹⁰].

OLLs are usually asymptomatic, but in some cases patients report pruritus, burning sensations, and pain in the affected region. As a polymorphic lesion OLL can present clinically as a white spot, a generalized ulceration, as striated, erythematous, erosive, or vesicular and occurring principally in the buccal mucosa, gingiva, or tongue [⁸,¹⁰,¹¹]. In the present case, the patient had an amalgam restoration in the region close to the lesion, which led to the OLL diagnosis.

Due to the challenge in differentiating and diagnosing lesions that fall within the OLM category, Aguirre-Urizar et al. [¹,¹²] and Van Der Meij [¹³] have proposed diagnostic procedures. Both authors reaffirm the need to correctly correlate clinical and histopathological characteristics in order to reach a definitive diagnosis. In the present case, a clinical diagnostic hypothesis of leukoplakia was initially assumed. However, the histopathological results revealed the presence of intense lymphocytic inflammatory infiltrate arranged in a band in the subepithelial region, and it became necessary to adjust the diagnosis to OLL.

Treatment of OLL consists of removing the irritant factor, anticipating either reduction or disappearance of the lesion. In some cases, where symptoms are intense, the use of topical or systemic corticosteroids is recommended [⁸,¹⁰] In accordance with the procedures outlined in the referenced literature, the patient was advised to replace the restorative amalgam material with resin and return for analysis and an adjusted prognosis.

Since OLM is a potentially malignant oral disorder with a low risk of malignancy (<3%) [⁴], the prognosis will depend on the subtype in question. OLL presents a statistically higher risk of malignant transformation than OLP [¹,⁴]. Gabusi et al. [¹⁴] reported a case of OLL which progressed to oral squamous cell carcinoma. Aguirre-Urizar et al. [¹] and Warnakulasuriya et al. [²] have both suggested, in agreement with the World Health Organization, that OLP and OLM should be grouped under the term “oral lichenoid disease”. However, Cheng et al. [⁵] emphasizes that distinction between these two lesions is necessary, since they present distinct biological behaviors. As such, in many cases of suspected OLL or OLP, it is necessary to perform a biopsy of the lesion to confirm the clinical diagnosis, rule out other diseases of the oral mucosa, and to evaluate the presence of epithelial dysplasia [²].

CONCLUSION

In conclusion, because OLL carry a higher risk of malignant transformation than OLP, it is essential to ensure accurate diagnosis, appropriate treatment, and careful monitoring through an integrated assessment of clinical and histopathological features − despite the significant diagnostic complexities involved.

• Article aligned with the Good Health and Well-Being and Quality Education goal of the Sustainable Development Goals (SDGs).
• How to cite this article Albuquerque ÉMC, Rodrigues LA, Siqueira GN, Sampieri MBS, Chaves FN, Oliveira DHIP. Challenges in the diagnosis of oral lichenoid lesions: a clinical case report. RGO, Rev Gaúch Odontol. 2026;74:e20260004. http://dx.doi.org/10.1590/1981-86372026000420250038

Data Availability

The research data are available in the body of the document.

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Edited by

• Assistant editor
  Luciana Butini Oliveira

Publication Dates

• Publication in this collection
  23 Mar 2026
• Date of issue
  2026

History

• Received
  01 May 2025
• Accepted
  06 June 2025