Current approaches to the diagnosis and treatment of white sponge nevus

Malignant transformation of white sponge nevus: a case report of a novel keratin 4 mutation

BACKGROUND

White Sponge Nevus (WSN) is traditionally considered a benign genetic disorder affecting the oral mucosa, primarily caused by pathogenic mutations in keratin 4 (KRT4) or keratin 13 (KRT13). Despite its benign nature, recent evidence has begun to question the malignant potential of WSN.

CASE PRESENTATION

We report a case involving a 70-year-old man who presented with a white lesion on the right floor of his mouth. Initial diagnostic evaluations confirmed the lesion as WSN. Over a one-year follow-up, the lesion underwent malignant transformation, evolving into local epithelial moderate-to-severe dysplasia. Exome sequencing identified a novel insertion mutation in exon 1 of the KRT4 gene, resulting in a deletion-insertion amino acid mutation involving glycine. Single-cell RNA sequencing further revealed altered epithelial proliferation and differentiation dynamics within the lesion.

CONCLUSIONS

This case not only expands the known genetic spectrum of KRT4 mutations associated with WSN but also provides preliminary evidence suggesting the malignant potential of WSN. The novel pathogenic mutation in KRT4 is postulated to alter epithelial proliferation and differentiation, thereby raising concerns about the malignant transformation of WSN. Further studies are warranted to confirm these findings.

Exfoliative Cytology and Genetic Analysis for a Non-Invasive Approach to the Diagnosis of White Sponge Nevus: Case Series

BACKGROUND

White Sponge Nevus (WSN) is a rare benign disorder associated with mutations in genes coding for cytokeratin 4 (KRT4) and 13 (KRT13) characterized by dyskeratotic hyperplasia of mucous membranes. This study was aimed at examining different approaches (cytology, pathology and genetic analysis) to WSN diagnosis.

METHODS

A series of four patients with asymptomatic white diffuse oral lesions were evaluated and, before performing an incisional biopsy for pathology, an oral brush Thin Prep was collected for exfoliative liquid-based cytology (LBC). DNA for genetic analysis was also obtained from patients and both their parents, using buccal swabs.

RESULTS

Pathology and cytology showed similar results, leading to the same diagnosis of hyperkeratotic epithelium with acanthosis and spongiosis, without atypia, demonstrating the efficiency of LBC for the differential diagnosis. Sequencing analysis revealed at least 6 rare variants in the KRT4 and KRT13 genes in each patient, contributed in part by both unaffected parents.

CONCLUSIONS

Thin Prep for oral exfoliative cytology and genetic analysis are sufficient for an accurate diagnosis of WSN. The combination of cytological and genetic analyses could substitute the histologic exam, providing a non-invasive alternative for incisional biopsy.

A Case Report on Familial White Sponge Nevus in Saudi Arabia

White sponge nevus (WSN) is an uncommon, benign, autosomal dominant disorder that usually appears at birth or in early childhood. It affects males and females equally and is caused by germ line mutations of the keratin genes leading to keratin instability and tonofilament aggregation. The condition causes painless, white, thickened, corrugated plaques to form on the oral mucosa, especially bilaterally on the buccal mucosa. Extra-orally, it occurs most often in the vaginal mucosa, as well as in the nasal and esophageal mucosa. In this report, we describe the case of a healthy 32-year-old Saudi male in Jizan in southern Saudi Arabia whose general dentist referred him to the oral medicine clinic at King Abdulaziz University Hospital, where he was diagnosed with white sponge nevus. The patient reported no medical problems and was a cigarette smoker for more than 10 years. An oral examination revealed white lesions affecting the buccal mucosa bilaterally and the labial mucosa. A biopsy of the buccal mucosa confirmed the diagnosis of white sponge nevus. Laser therapy was suggested for the aesthetic treatment of the lesions. Better awareness of this hereditary condition among dental professionals can help improve timely diagnoses early in life and thus avoid unnecessary or inadequate treatment for this benign condition.

White Sponge Nevus Caused by Keratin 4 Gene Mutation: A Case Report

White sponge nevus (WSN) is a rare autosomal dominant disease with a family history, often caused by mutations of the keratin 4 (K4) and keratin 13 (K13) genes in patients. It is characterized by frequently occurred white corrugated folds in the bilateral buccal mucosa with soft texture. On histopathological examination, hyperkeratosis of epithelial cells, edema, and vacuolar changes in the spinous cells are observed in the lesions, despite a normal layer of basal cells. WSN should be differentiated from other oral white spot diseases, mainly oral lichen planus, oral candidiasis, oral white edema, and Heck's disease, to reduce misdiagnosis and unnecessary treatment. At present, there is no specific treatment method. The purpose of this study was to report the clinical data of four WSN patients of the same family with the K4 gene mutation. The occurrence of WSN in a pair of monozygotic twins with very similar clinical presentations was identified for the first time. The gene sequencing results showed that there was a heterozygous deletion (C. 438_440delCAA) in exon 1 of the K4 gene, resulting in an aspartic acid loss in both the proband and his father. Finally, the etiology, pathogenesis, pathological manifestations, clinical manifestations, diagnosis, differential diagnosis, and related treatment methods are discussed to provide a reference for clinical treatment of the disease.

Oral Mucosal Lesions in Childhood

Childhood diseases are a continuous source of interest in all areas of general and dental medicine. Congenital, developmental, and hereditary diseases may either be present upon birth or appear in early childhood. Developmental anomalies, although often asymptomatic, may become grounds for different infections. Furthermore, they can indicate certain systemic disorders. Childhood age frequently brings about benign tumors and different types of traumatic lesions to the oral mucosa. Traumatic lesions can be caused by chemical, mechanical, or thermal injury. Mucocele and ranula are, by definition, traumatic injuries of the salivary glands or their ducts. Recurrent aphthous lesions are the most common type of ulcerations in childhood, and their etiology is considered multifactorial. Oral mucosal lesions in children require different treatment approaches depending on etiological factors and clinical presentation. Clinicians should have adequate knowledge of oral anatomy in order to diagnose and treat pathological conditions.

Two white sponge nevus in a single family: case report

Introduction: White Sponge Nevus (WSN) is a leukokeratosis characterized by white lesions of the oral mucosa. These lesions are bilateral, thickened and raised compared to the adjacent mucosa. Their aspect are folded and spongy. It is a benign disorder with asymptomatics lesions which often appear during the childhood or the adolescence. The interest of this case report is that the diagnostic of WSN had been established directly, thanks to the presence of the patient's father. Observation: A twelve years old patient was examined in the unity of the oral mucosa pathology and oro-facials pain, of the oral surgery service of Bordeaux hospital (CHU de Bordeaux, France). He presented typical WSN lesions. His father was examined and presented the same lesions. Discussion: Diagnostic of WSN is mainly a clinical examination. There are a lot of differential diagnosis, and leukoplakia is the principal. In case of doubt about the diagnostic, a histological examination can be done. Nowadays, there is no consensus about the therapeutic. But the lesions are mainly asymptomatics, so any treatment has to be planed. Conclusion: An early WSN diagnosis avoids to patients a non adapted treatment and reassures young patients and their parents.

Keratin 13 deficiency causes white sponge nevus in mice

White sponge nevus (WSN) is a benign autosomal dominant disorder characterized by the formation of white spongy plaques in the oral mucosa. Keratin (KRT) 13 is highly expressed in the mucosa, and mutations in this gene have been commonly associated with WSN patients. However, it remains unknown whether there is a causal relationship between KRT13 mutations and WSN and what the underlying mechanisms might be. Here, we use mouse genetic models to demonstrate that Krt13 is crucial for the maintenance of epithelial integrity. Krt13 knockout mice show a WSN-like phenotype in several tissues, including the tongue, buccal mucosa, and esophagus. Transcriptome analyses uncover that Krt13 regulates a cohort of gene networks in tongue epithelial cells, including epithelial differentiation, immune responses, stress-activated kinase signaling, and metabolic processes. We also provide evidence that epithelial cells without Krt13 are susceptible to mechanical stresses experienced during postnatal life, resulting in unbalanced cell proliferation and differentiation. These data demonstrate that Krt13 is essential for maintaining epithelial homeostasis and loss of Krt13 causes the WSN-like phenotype in mice.

Large Cell Acanthoma of the Conjunctiva: Clinicopathologic and Immunohistochemical Features

Large cell acanthoma (LCA) was first described as a lesion on sun-exposed skin. All LCAs feature keratinocytes twice the size of normal cells (cytomegaly). Although infrequently diagnosed in the skin, it has been even more rarely described by ophthalmic pathologists in the eyelid skin and the conjunctiva. This report describes the third case of a conjunctival epithelial LCA, with the first published clinical photograph highlighting its leukoplakic and well-circumscribed character, as well as the most thorough analysis of the immunohistochemical features of this lesion. It is contrasted with squamous dysplasias and papillomas of the conjunctiva. A review of previous conjunctival LCA lesions discloses frequent recurrences after initial surgery and the remote but real potential for squamous dysplastic transformation. Immunohistochemical stains for certain cytokeratins, p53, and Ki-67 (proliferation index) will in the future be particularly helpful in establishing an early and accurate diagnosis of conjunctival LCA.

Frictional Keratosis, Contact Keratosis and Smokeless Tobacco Keratosis: Features of Reactive White Lesions of the Oral Mucosa

White lesions of the oral cavity are quite common and can have a variety of etiologies, both benign and malignant. Although the vast majority of publications focus on leukoplakia and other potentially malignant lesions, most oral lesions that appear white are benign. This review will focus exclusively on reactive white oral lesions. Included in the discussion are frictional keratoses, irritant contact stomatitis, and smokeless tobacco keratoses. Leukoedema and hereditary genodermatoses that may enter in the clinical differential diagnoses of frictional keratoses including white sponge nevus and hereditary benign intraepithelial dyskeratosis will be reviewed. Many products can result in contact stomatitis. Dentrifice-related stomatitis, contact reactions to amalgam and cinnamon can cause keratotic lesions. Each of these lesions have microscopic findings that can assist in patient management.

Keratin 4 regulates the development of human white sponge nevus

BACKGROUND

The aim of this study was to investigate the roles of keratin 4 (KRT4) gene in the development of human white sponge nevus (WSN).

METHODS

Transgenic mice were created using the microinjection method with pcDNA3.1 vectors expressing KRT4 wild-type (WT) gene and E520K mutation. Polymerase chain reaction (PCR) and Western blotting were used to identify the genotype of transgenic founders and their filial generations. Expression of KRT4 in mouse oral mucosa was characterized by immunohistochemistry (IHC), and the whole epithelium layer of transgenic mice was observed using transmission electron microscope (TEM).

RESULTS

The positive rate of KRT4 transgenic mice in F1 generation was 45.5%. Expression level of KRT4 protein was significantly higher in 2-month-old transgenic mice than WT mice. Furthermore, all the epithelial lamina of 3-month-old transgenic mice showed reduced staining of KRT4. The surface and spinous layers were full of hyalocytes and bubble cells, which are similar to the clinical symptoms of WSN. For the ultrastructure, both tonofilaments and Odland bodies increased.

CONCLUSIONS

Our study indicated the mutated KRT4 gene may play important roles in the pathogenesis of WSN.

White sponge nevus: Report of three cases in a single family

White sponge nevus (WSN) is an interesting hereditary oral mucosal disorder that commonly manifests as bilaterally symmetrical, thickened white, corrugated or velvety, diffuse plaques that predominantly affects the buccal mucosa. The lesions may develop at birth or later in childhood or adolescence. Because it is asymptomatic and benign, WSN requires no treatment. Recognition of this disorder is important due to its potential confusion with other lesions that may be found in the oral cavity. Emphasis should be given to the early and correct diagnosis of this disorder to avoid unnecessary treatment. This report presents three affected members of a single family.