Life-threatening disorders of mucous membranes Yalc ¸in Tu ¨zu ¨n, MD * , Aylin Kalayciyan, MD, Burhan Engin, MD, Binnur Tu ¨zu ¨n, MD Department of Dermatology, Cerrahpasa Medical Faculty, Istanbul University, Aksaray, Istanbul 34098, Turkey Trakya University Medical Faculty, 22030 Edirne, Turkey Abstract Oral mucosa is one of the first barriers to the outside world which encounters various antigens, microorganisms and physical agents. Numerous oral pathologies challenge the dermatologists. Some may be the first sign of an underlying immunosuppression, while others are the inevitable serious outcomes of long-lasting mucosal disease. The differential diagnosis is crucial in terms of prompt and effective treatment. D 2005 Elsevier Inc. All rights reserved. Introduction A variety of serious disorders of mucous membranes is recognized in immunosuppressed patients and even in healthy hosts. The more common ones include oral manifestations of systemic disease, various infections, immunologic-based mucosal diseases, and so on. 1 In children, oral lesions are not necessarily associated with immunosuppression. Sometimes poor oral hygiene habits and poor nutrition may be involved. 2 Epithelial pathologies Leukoplakia Leukoplakia is a clinical entity defined by the World Health Organization as ba white patch or plaque that cannot be characterized clinically or pathologically as any other diseaseQ. 1 The most common site of involvement is the ven- trolateral surface of the tongue, but it may infrequently be found on the cheek mucosa, lip mucosa, floor of the mouth, soft palate, and oropharyngeal mucosa. 2 In addition, most leukoplakias mainly affects males, and a growing prevalence of precancerous lesions with increasing age is reported. Leukoplakia seems to be commonly associated with some factors such as tobacco smoking and also smokeless tobacco use, alcohol exposure, and frictional irritation. The demonstration of the presence of Epstein-Barr virus may sometimes be necessary to diagnose the disease. The degree of severity of oral leukoplakias is important. As anticipated, the question is whether oral leukoplakia is a malignant condition or just a symptom. Lesions occurring on the floor of the mouth, ventral tongue, lateral tongue, and soft palate may be more likely to exhibit significant histopathologic findings. Therefore, it is important to have a biopsy to assess the follow-up strategies. The presence of an erythroplakic component or verrucous features in the lesions is evidence for an early carcinoma. Neville and Day, in 2000, suggested that molecular markers such as DNA content and loss of heterozygosity hold promise of becoming important tools for predicting risk of malignant transformation of oral leukoplakia. 3 According to some authors, the condition generically referred to as leukoplakia fulfills histopathologic criteria for 0738-081X/$ – see front matter D 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.clindermatol.2004.06.007 * Corresponding author. Department of Dermatology, Cerrahpasa Medical Faculty, Istanbul University, Aksaray, Istanbul 34098, Turkey. E-mail address: yalcintuzun@superonline.com (Y. Tu ¨zu ¨n). Clinics in Dermatology (2005) 23, 267–275