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Vulvar Intraepithelial Neoplasia

By ProPath Staff


A case report of vulvar carcinoma in a 39-year old 

The term vulvar intraepithelial neoplasia (VIN) was introduced in the early 1980’s as a generic designation for severe squamous epithelial atypia (severe dysplasia) and squamous cell carcinoma in-situ (CIS) of the vulva. The VIN terminology was adopted by the International Society for the Study of Vulvar Disease in 1986, the World Health Organization and International Society of Gynecologic Pathologists in 1994. According to these classifications, VIN lesions are graded depending on the level of involvement of the affected epidermis, by cellular disarray, nuclear atypia, and mitotic activity. In VIN I (mild dysplasia), the lowest third is involved: In VIN II (moderate dysplasia), the lower 2/3, in VIN III (severe dysplasia/CIS), greater than 2/3 of the epithelium is involved.

VIN has been classified into two distinct types: Classic (bowenoid) and Simplex (differentiated). Classic VIN has a predilection for relatively young women, often in their 30’s and 40’s, and has been associated with risk factors such as cigarette smoking, condylomas, a history of herpes genitalis, and HIV positivity. HPV nucleic acids are found in 53 – 90% of classic VIN cases with HPV-16 the predominant genotype. The microscopic appearance of classic VIN includes a thickened epidermis with disorganization of keratinocytes, high nuclear to cytoplasmic ratio, nuclear hyperchromasia, irregularities of the nuclear membranes, and numerous mitotic figures at all levels of the epidermis. Multipolar and abnormal mitotic figures are easily found.

The other major type of VIN is the Simplex (differentiated) type. It is this type that has been proposed as the probable pre-cursor of many if not most invasive squamous cell carcinomas (SCCs) of the vulva. Simplex VIN characteristically occurs in post-menopausal women. The mean age is 67 years, more than two or three decades older than patients with classic VIN. About 25% of patients have a documented history of cigarette smoking. VIN found in patients with lichen sclerosis and vulvar dystrophy is usually of the simplex type. Histologically, simplex VIN is a dramatically more subtle lesion than classic VIN. It is easily mistaken for ordinary squamous hyperplasia or acanthosis. Microscopically, the epidermis is thickened and has a parakeratotic surface reaction. The rete ridges are often elongated and frequently branched. In spite of the relatively orderly appearance of epidermal maturation, most of the epidermis is composed of abnormal squamous cells. HPV is almost always absent in simplex VIN and is usually not found in the vulvar invasive SCC’s that are associated with simplex VIN. This is in contrast to classic VIN and the vulvar SCC’s derived from them, which are HPV positive in the vast majority of cases.

The most common symptoms of vulvar cancer include pruritis, a visible or palpable mass, pain, bleeding, ulceration, dysuria, and vaginal discharge. It is common for patients to delay seeking medical attention or for there to be a delay in diagnosing the condition as demonstrated by the findings of the Gynecologic Oncology Group. They found that up to 39% of women presented with advanced stage disease (Stage 3 or 4).

The case presented here is that of a 39-year-old woman, with a 6-year history of vulvar lesions. At surgery, an 18.5 cm. radical vulvectomy specimen was obtained. Grossly there were flat, white, plaque-like lesions involving the entire vulva. An 8 cm. firm, flat, yellow-tan irregular mass was located inferiorly and predominately right of the midline. Microscopic examination revealed an 8 cm. moderately differentiated invasive squamous cell carcinoma with a maximum invasion of 8 mm. One of thirteen lymph nodes contained metastatic carcinoma. VIN III was identified adjacent to the invasive cancer.

In the United States, vulvar cancer is the fourth most common gynecologic cancer. There are 2,500 new cases in the United States each year and the incidence is rising. Prior to the 1960’s, the incidence of vulvar cancer was approximately 5%. Currently, the incidence has risen to 8%. With an increasing incidence of HPV-related VIN worldwide, there is an associated increasing incidence of invasive vulvar carcinoma in young women, a fact that demands the awareness of both women and their physicians.

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