White sponge nevus.

A 33-year-old-man presented with a 13-year history of asymptomatic, white, folded, soft, poorly-demarcated, diffuse plaques bilaterally on his buccal mucosae and lateral surfaces of his tongue. There is no family history of similar lesions. The physical examination and histopathologic findings were consistent with a diagnosis of white sponge nevus. This rare disorder is typically inherited; however, as in this case, there have been a few other cases reported without a familial background.