Familial Case of White Sponge Nevus - Diagnosis and Therapeutical Challenges.

White sponge nevus (WSN) is a rare autosomal dominant disorder with variable penetrance (1). It was first described by Hyde in 1909 (2); in 1935 Cannon named it white sponge nevus (3). Several other names have been applied to this condition: HydeCannon’s disease, familial white folded dysplasia, congenital leukokeratosis mucose oris, hereditary leukokeratosis, and white folded gingivostomatosis. The lesions of WSN involve non-cornified stratified epithelia, especially of the oral mucosa. The suspected mechanism is a keratinization defect (1), mutations of keratin genes 4 and 13 being likely. These mutations lead to the disruption of the intracellular filament network (4-6). WSN is characterized by the presence of whitegreyish, folded, spongy, and thickened plaques on the oral mucosa that are usually asymptomatic. Occasionally, extraoral sites are involved. WSN of the vaginal, rectal, nasal, and esophageal mucosa have been described (7). The lesions are most often present at birth or develop in early childhood, but due to the lack of associated symptoms they are discovered only incidentally and are frequently misdiagnosed as candidiasis (8). Diagnosis requires a high index of suspicion. A biopsy is generally needed for differential diagnosis. Apart from hyperkeratosis and acanthosis of the affected epithelium, histopathological examination reveals the characteristic eosinophilic perinuclear condensation representing aggregation of cytokeratin filaments (9,10). We report a case of WSN in an otherwise healthy white male with a familial history of similar lesions in 6 other family members from three generations. An 18-year-old non-smoker male patient was referred to our Department for a 13-year history of white verrucous bilateral plaques on the oral mucosa. Presumed to be oral candidiasis, this condition had been recurrently treated with systemic or topical antifungal therapies and with local antiseptics, without clinical benefit. Even though the lesions were asymptomatic, the patient was extremely concerned about their nature, as well as their unaesthetic aspect. Clinical examination revealed a rough, folded surface of the oral mucosa, presenting thick white plaques, involving the soft and hard palate, the jugal mucosa, the gingiva, the ventral tongue, the floor of the mouth, and the labial mucosa (Figure 2, 3). Although the large plaques were firmly attached to the underlying tissue, small fragments peeled away revealing a pale, thin mucosa. We also noticed good oral hygienic status, healthy teeth, and the absence of cervical adenopathies. No extraoral sites were involved. Blood tests results were within normal ranges, including immunogram, human immunodeficiency virus (HIV), and lupus erythematosus serology. Oral bacterial and fungal infections were excluded based on negative cultures.