eMedicine Specialties > Obstetrics and Gynecology > General Gynecology

Nonneoplastic Epithelial Disorders of the Vulva

Author: Michel E Rivlin, MD, Associate Professor, Coordinator, Quality Assurance/Quality Improvement, Department of Obstetrics and Gynecology, University of Mississippi School of Medicine
Contributor Information and Disclosures

Updated: Jul 9, 2007

Introduction

Background

Symptoms related to vulvar disorders include pruritus, vulvodynia, superficial dyspareunia, or lesions that may be white, red, pigmented, raised, or ulcerated. These symptoms may be caused by infections, dermatologic disorders, or nonneoplastic or neoplastic vulvar diseases.

Successive meetings of several international societies have resulted in the development of a standardized nomenclature based on histopathologic findings. The older terms, such as vulvar dystrophy, kraurosis vulvae, leukoplakia, hyperplastic vulvitis, and lichen sclerosus et atrophicus, should no longer be used. In their places, nonneoplastic epithelial disorders were divided into 3 major categories: squamous cell hyperplasia, lichen sclerosus, and other dermatoses. Vulvar lesions with atypia were excluded from the classification.

Mixed epithelial disorders may occur and, in such cases, all conditions are reported. If atypia is present, the diagnosis is vulvar intraepithelial neoplasia (VIN), which may be differentiated or undifferentiated, depending on the degree of atypia. A further reclassification includes lichen sclerosus under inflammatory skin conditions, further grouped as a lichenoid disorder, while squamous hyperplasia is under psoriasiform disorders as lichenification, encompassing the term lichen simplex. Unfortunately, although the terminology may be comprehensive, it does not clarify the link with vulvar cancer.

Included in the differential diagnosis of lichen sclerosus and squamous cell hyperplasia are other dermatoses (eg, psoriasis, lichen planus), as well as benign lesions (eg, hidradenoma) and potentially malignant lesions (eg, Paget disease, VIN, melanoma).

Pathophysiology

Lichen sclerosus may involve the pudendum, perineum, and perianal areas. The skin is white and thin, although concurrent squamous cell hyperplasia with skin thickening may be present. Squamous cell carcinoma (SCC) may occur in these areas, with some studies reporting it as frequently as 3-5% in women with lichen sclerosus. Microscopically, skin atrophy is observed.

Squamous cell hyperplasia is usually asymmetrical, ranging from white to gray, with coarsely thickened skin. Microscopically, epithelial thickening is observed. The hyperplastic changes may be associated with the trauma of scratching caused by the intense pruritus, especially in untreated women. However, whether treatment lessens the risk of malignancy is not known.

In most cases, epithelial alterations are adjacent to invasive SCC of the vulva. Two distinct entities have been noted: (1) the common keratinizing SCC affecting an older population and arising in the background of a nonneoplastic epithelial disorder, lichen sclerosus, and/or squamous hyperplasia and (2) the human papillomavirus (HPV)–related carcinoma arising from undifferentiated VIN III, commonly in young women. Furthermore, a significant difference in prognosis has been observed, with HPV-related cases having better outcomes.

The nature of the interrelationship is obscure because lichen sclerosus and squamous hyperplasia appear to be benign conditions without malignant potential, being polyclonal and without allelic imbalance or p53 expression. However some cases have been shown to have monoclonality, increased p53 expression, allelic imbalance, and aneuploidy. It has been postulated that allelic alterations can occur in morphologically benign conditions producing clonal expansion. Additional molecular events, either host or viral, lead to atypia as dedifferentiated (HPV+) or differentiated (HPV-) VIN in the progression to invasive cancer.

Frequency

United States

The prevalence of lichen sclerosus is not known, but the condition is thought to be relatively uncommon. Most cases occur in postmenopausal women, although it is known to occur in prepubescent girls. Squamous cell hyperplasia, primarily a disease of older women, is relatively uncommon.

Mortality/Morbidity

• Mortality is associated with the rare occurrence of SCC that complicates lichen sclerosus or squamous cell hyperplasia.
• Morbidity is associated with severe symptomatology and interference with sexual function for both lichen sclerosus and squamous cell hyperplasia.

Race

No racial differences have been noted.

Sex

Vulval lichen sclerosus and squamous cell hyperplasia occur in female patients.

Age

These conditions usually occur in postmenopausal women, although lichen sclerosus is not uncommon in prepubertal girls

Clinical

History

Patients with lichen sclerosus and squamous cell hyperplasia usually present with pruritus vulvae, vulvodynia, superficial dyspareunia, or visible lesions.

Physical

Lichen sclerosus is characterized by "cigarette paper" skin, ie, skin that is thin, white, and crinkly. The introitus may shrink with fusion of the labia minora.

Squamous cell hyperplasia has a nonspecific appearance with thickened asymmetrical areas and a coloration ranging from white to gray.

Causes

The etiology of lichen sclerosis is unknown. Familial incidence is well recognized and may concern both sexes. The link with autoimmune disease is also established but relatively weak. Approximately 21% of patients have an autoimmune disease, most commonly a thyroid disorder. Twenty-two percent of patients have a family history, and 44% have one or more autoantibodies. Many studies, including those that relate to HLA findings, those that seek an infectious agent, and those that investigate cell kinetics, have not yielded any consistent theories regarding the etiology and pathophysiology of these disorders. Patients with a genetic predisposition or with associated autoimmune disorders do not differ clinically from those without such a background.

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