White sponge nevus

A genetic condition affecting the mucous membranes

White sponge nevus

Diagram of autosomal dominant inheritance

White sponge nevus (WSN) is a rare genetic disorder characterized by the presence of white, spongy plaques on the mucous membranes, primarily affecting the oral cavity. It is a benign condition that typically presents in childhood or adolescence.

Etiology

White sponge nevus is caused by mutations in the keratin genes, specifically KRT4 and KRT13, which are responsible for the structural integrity of epithelial cells in the mucous membranes. The condition follows an autosomal dominant pattern of inheritance, meaning that a single copy of the mutated gene from an affected parent can cause the disorder in offspring.

Clinical presentation

The most common manifestation of white sponge nevus is the appearance of white, thickened, and spongy plaques on the buccal mucosa, although other areas such as the gingiva, tongue, and floor of the mouth may also be involved. These lesions are usually asymptomatic, but some patients may experience mild irritation or discomfort.

Diagnosis

Diagnosis of white sponge nevus is primarily clinical, based on the characteristic appearance of the lesions. A biopsy may be performed to confirm the diagnosis, revealing hyperparakeratosis and acanthosis of the epithelium. Genetic testing can identify mutations in the KRT4 or KRT13 genes, providing a definitive diagnosis.

Management

There is no specific treatment required for white sponge nevus, as it is a benign condition. Management focuses on reassurance and monitoring for any changes in the lesions. In cases where the lesions cause significant discomfort, topical treatments or surgical removal may be considered.

Prognosis

The prognosis for individuals with white sponge nevus is excellent, as the condition does not predispose to malignancy or other serious complications. The lesions typically persist throughout life but do not usually cause significant health issues.

Related pages

• Oral mucosa
• Genetic disorder
• Keratin