white sponge nevus
An inherited dermopathy* characterised by variably-sized, painless, whitish plaques which, by light microscopy, display a “basket-weave” epithelium, hyperparakeratosis and acanthosis. White sponge nevus (WSN) occur on nasopharyngeal, oral, oesophageal, laryngeal, vaginal, and anal mucosae.
*Two genetic forms have been described, WSN 1 (OMIM:193900) and WSN 2 (OMIM:615785).
Differential diagnosis Waxing and waning WSNs may simulate other white lesions of the mouth–e.g., leukoedema, leukoplakia, irritation, chewing tobacco dysplasia, lichen planus, Darier’s disease, dyskeratosis congenita.
Molecular pathology Defects of
• KRT4, which encodes a keratin, cause WSN 1 (OMIM:193900).
References, WSN1 http://www.genecards.org/cgi-bin/carddisp.pl?gene=KRT4
• KRT13, which encodes a keratin, cause WSN 2 (OMIM:615785).
References, WSN2 http://www.genecards.org/cgi-bin/carddisp.pl?gene=KRT13