White sponge nevus is a rare genetic condition inherited in most cases as an autosomal dominant trait caused by mutations in either the keratin 4 or keratin 13 genes. Lesions may be evident at birth or early in childhood, but occasionally appear in the second decade.

Asymptomatic diffuse white plaques affect the buccal mucosa bilaterally. The degree of involvement varies considerably. Other oral mucosal sites of involvement may include ventral tongue, labial mucosa, floor of mouth and soft palate. Less commonly, other mucosal sites (anogenital, esophageal, nasal, laryngeal) may be affected.