Oral White Sponge Nevus: A Rare Case Report

ABSTRACT

White sponge nevus (WSN) is a rare, benign genetic disorder characterized by distinctive white or gray mucosal lesions, most commonly affecting the oral cavity. Inherited in an autosomal dominant pattern, WSN results from mutations in keratin genes—primarily KRT4 and KRT13. These mutations lead to the development of thick, spongy plaques in the oral mucosa, with extraoral involvement more commonly associated with KRT13 mutations. The condition typically manifests in early childhood, presenting as painless, persistent white plaques. Diagnosis is usually based on clinical evaluation, although histopathological examination can provide confirmation. WSN is generally asymptomatic and does not require treatment; however, its cosmetic appearance may cause psychological discomfort. Although malignant transformation is rare, certain antimicrobial therapies have shown promise in symptom management. This report describes a case of WSN in a 23‐year‐old Iranian woman, detailing the clinical presentation, diagnostic process, and potential treatment strategies. Despite its benign nature, further research into the pathogenesis and therapeutic options is essential to improve patient care and quality of life.

Summary.

• White sponge nevus, a rare genodermatosis, warrants further study to understand its underlying mechanisms, potential risk of malignant transformation, and the pursuit of an effective curative treatment.

1. Introduction

White sponge nevus (WSN) is a rare, benign genetic disorder affecting mucous membranes and, occasionally, the skin. It is inherited in an autosomal dominant pattern, characterized by high penetrance and variable expressivity. The condition is caused by mutations in keratin genes—specifically keratin 4 (KRT4) and keratin 13 (KRT13)—located on chromosomes 12q13 and 17q21–q22, respectively [1, 2]. Originally described by Hyde in 1909, the disorder was later named “white sponge nevus” by Cannon in 1935. WSN typically presents at birth or during early childhood, although onset in adolescence has also been reported. It affects males and females equally [3].

2. Case History/Examination

The subject of this case study is a 23‐year‐old Iranian woman with a history of surgically repaired mitral valve prolapse. She occasionally takes propranolol during periods of stress. She reported no history of smoking or alcohol consumption. She presented to the Oral and Maxillofacial Medicine Center with a chief complaint of a persistent oral lesion. According to the patient, the lesion has been present since childhood and does not exhibit periods of remission or exacerbation (Figures 1 and 2). The lesion's size has remained stable over time, although she noted occasional mucosal shedding—typically occurring in the morning while rinsing her mouth or after prolonged periods without food. She reported no pain or burning sensation. She had not received any prior treatment for the condition.

FIGURE 1.

Intraoral examination indicates painless, white, thickened, spongy and corrugated plaques in labial and buccal mucosa, retromolar area, soft palate, and pharyngeal walls that do not fade when the tissue is stretched.

FIGURE 2.

Intraoral examination indicates painless, white, thickened, spongy and corrugated plaques in labial and buccal mucosa, retromolar area, soft palate, and pharyngeal walls that do not fade when the tissue is stretched.

Clinical examination revealed diffuse, painless, white, thickened, spongy, and corrugated plaques involving the right and left buccal mucosa, upper and lower labial mucosa, retromolar areas, soft palate, and pharyngeal walls. The lesions did not disappear upon stretching of the mucosa. Sloughing was observed in some areas.

3. Differential Diagnosis, Investigations, and Treatment

An incisional biopsy was obtained from the buccal mucosa and submitted for histopathological evaluation, with a possible diagnosis of WSN. Although leukoplakia, chronic candidiasis, and autoimmune diseases like oral lichen planus may present similarly, the typical clinical features and history in this case supported WSN as the definitive diagnosis. Microscopic examination revealed acanthosis, cellular vacuolization, dyskeratosis, and the presence of anuclear cells in the superficial epithelium. Mild inflammation was observed in the lamina propria (Figure 3). Based on these findings, a definitive diagnosis of WSN was established. The absence of candidial hyphae invading the epithelium, along with the lack of band‐like lymphocytic infiltration in the lamina propria, effectively excluded chronic candidiasis and oral lichen planus from the differential diagnosis.

FIGURE 3.

Displaying acanthosis, cellular vacuolization, dyskeratosis, anuclear cells in the superficial epithelium and mild inflammation in lamina propria (H&E staining, Magnification ×10).

Given the benign nature of the lesion, no specific treatment was deemed necessary.

4. Conclusion and Results (Outcome and Follow‐Up)

The patient was advised to perform regular self‐examinations and to consult an Oral and Maxillofacial Medicine specialist if any symptoms or notable changes in the size or appearance of the lesion occurred.

In conclusion, WSN is a rare, benign genetic disorder characterized by distinctive oral mucosal lesions resulting from mutations in keratin genes. Although the condition typically presents without significant symptoms and is often diagnosed through clinical examination, it may pose aesthetic concerns for affected individuals. Despite its generally favorable prognosis, the potential for rare malignant transformation and the variable expression of symptoms underscore the importance of clinical awareness among healthcare providers.

Future research should aim to elucidate the underlying pathophysiological mechanisms of WSN and investigate therapeutic approaches that may alleviate discomfort or enhance patients' quality of life. Although WSN remains a benign condition, ongoing vigilance and scientific inquiry are essential to ensure optimal care for those affected.

5. Discussion

White sponge nevus is a rare inherited condition, affecting approximately 1 in 200,000 individuals. It primarily involves the oral mucosa, with common sites including the buccal mucosa (often bilaterally), lips, alveolar ridges, ventral tongue, labial mucosa, soft palate, and the floor of the mouth. Less frequently, WSN may affect the mucosal membranes of the esophagus, larynx, nasal cavity, and anogenital regions [1, 2, 4, 5, 6]. Extra‐oral lesions are typically associated with mutations in KRT13 [7].

The hallmark lesions of WSN are painless, white or gray, thickened, spongy, or corrugated plaques that do not disappear upon stretching of the mucosa [1, 2, 4]. Accurate diagnosis requires differentiation from other malignant, reactive, familial, and congenital conditions. Although diagnosis is usually clinical—based on lesion appearance—a biopsy may be warranted when the presentation mimics other white mucosal disorders. Histopathological confirmation can aid in distinguishing WSN from similar entities [8].

Although WSN is considered benign, rare cases of malignant transformation have been reported [1]. The overall prognosis is favorable [4]. Despite being typically asymptomatic and not requiring treatment, the altered mucosal texture and aesthetic impact may cause discomfort for some patients. Various therapeutic approaches have been explored, but their efficacy remains inconsistent, and no standardized treatment protocol exists [3, 9].

Interestingly, although WSN is not of microbiological origin, some antimicrobial therapies—such as oral and topical antibiotics and antiseptics like chlorhexidine—have shown promising results in managing secondary infections or mucosal hygiene improvement [10]. This raises the possibility that microbial factors may influence disease expression in genetically predisposed individuals, though further research is needed to substantiate this hypothesis. One case report documented a positive clinical response to oral doxycycline (100 mg/day for 6 weeks), suggesting potential benefit from tetracycline‐class antibiotics; however, additional studies are required to evaluate their effectiveness in managing WSN [9].

Author Contributions

Maryam Hosseinpour Sarmadi: conceptualization, data curation, investigation, writing – review and editing. Farshad Javadzadeh: conceptualization, data curation, project administration, supervision, validation, visualization, writing – review and editing. Mahsa Taghavi Zenouz: validation, visualization, writing – review and editing. Mina Zohrabi: investigation, methodology, resources, writing – original draft, writing – review and editing.

Consent

A written informed consent was obtained from patient to publish this report in accordance with the journal's patient consent policy.

Conflicts of Interest

The authors declare no conflicts of interest.

Hosseinpour Sarmadi M., Javadzadeh F., Taghavi Zenouz M., and Zohrabi M., “Oral White Sponge Nevus: A Rare Case Report,” Clinical Case Reports 13, no. 9 (2025): e70833, 10.1002/ccr3.70833.

Data Availability Statement

The data that support the findings of this study are available in this article.