Medically speaking, the term denotes a squamous intraepithelial lesion of the vulva that shows dysplasia with varying degrees of atypia. The epithelial basement membrane is intact and the lesion is thus not invasive but has invasive potential.

The terminology of VIN evolved over several decades. In 1989 the Committee on Terminology, International Society for the Study of Vulvar Disease (ISSVD) replaced older terminology such as vulvar , Bowen's disease, and Kraurosis vulvae by a new classification system for "Epithelial Vulvar Disease":

- Nonneoplastic epithelial disorders of vulva and mucosa:

- Lichen sclerosus

- Squamous hyperplasia

- Other dermatoses

- Mixed neoplastic and nonneoplastic disorders

- Intraepithelial neoplasia

- Squamous vulvar intraepithelial neoplasia (VIN)

- VIN I, mildest form

- VIN II, intermediate

- VIN III, most severe form including carcinoma in situ of the vulva

- Non-squamous intraepithelial neoplasia

- Extramammary Paget's disease

- Tumors of melanocytes, noninvasive

- Invasive disease (vulvar carcinoma)

The ISSVD further revised this classification in 2004, replacing the three-grade system with a single-grade system in which only the high-grade disease is classified as VIN.

VIN is subdivided into: (Robbins Pathological Basis of Disease, 9th Ed)

Classic vulvular intraepithelial neoplasia: associated with developing into the warty and basaloid type carcinoma. This is associated with carcinogenic genotypes of HPV and/or HPV persistence factors such as cigarette smoking or immunocompromised states.

Differentiated vulvar intraepithelial neoplasia also known as VIN Simplex: is associated with vulvar dermatoses such as lichen sclerosus. It is associated with atypia of the squamous epithelium.

The patient may have no symptoms, or local symptomatology including itching, burning, and pain.

The diagnosis is always based on a careful inspection and a targeted biopsy of a visible vulvar lesion.

The type and distribution of lesions varies among the two different types of VIN. In the Usual type VIN, seen more frequently in young patients, lesions tend to be multifocal over an otherwise normal vulvar skin. In the differentiated type VIN, usually seen in postmenopausal women, lesions tend to be isolated and are located over a skin with a vulvar dermatosis such as Lichen slerosus.

The most common location by far is the gingival margin and other areas of the masticatory oral mucosa, these occur more frequently in the fifth decade of life, and have good prognosis, the treatment of choice for oral VXs is surgical excision, and recurrence is rare.

The condition can affect other organs of body, such as the penis, vulva, and can occur in anal region, nose, the ear, lower extremity, scrotum.

Differential diagnosis includes seborrheic keratosis, verruca simplex, condyloma acuminatum, granular cell myoblastoma, vulvar intraepithelial neoplasia, bowenoid papulosis, erythroplasia of Queyrat, and verrucous carcinoma

Adnexal and skin appendage neoplasms is a group of tumors which develop in the adnexal skin structures such as the sweat and sebaceous glands. An example is the hidrocystoma.

Many malignancies can develop in vulvar structures. The signs and symptoms can include:

- Itching, burn, or bleeding on the vulva that does not go away.

- Changes in the color of the skin of the vulva, so that it looks redder or whiter than is normal.

- Skin changes in the vulva, including what looks like a rash or warts.

- Sores, lumps, or ulcers on the vulva that do not go away.

- Pain in the pelvis, especially during urination or sex.

Typically, a lesion presents in the form of a lump or ulcer on the labia majora and may be associated with itching, irritation, local bleeding or discharge, in addition to pain with urination or pain during sexual intercourse. The labia minora, clitoris, perineum and mons are less commonly involved. Due to modesty or embarrassment, patients may put off seeing a doctor.

Melanomas tend to display the typical asymmetry, uneven borders and dark discoloration as do melanomas in other parts of the body.

Adenocarcinoma can arise from the Bartholin gland and present with a painful lump.

Individuals with a basal-cell carcinoma typically present with a shiny, pearly skin nodule. However, superficial basal-cell cancer can present as a red patch similar to eczema. Infiltrative or morpheaform basal-cell cancers can present as a skin thickening or scar tissue – making diagnosis difficult without using tactile sensation and a skin biopsy. It is often difficult to visually distinguish basal-cell cancer from acne scar, actinic elastosis, and recent cryodestruction inflammation.

The histopathologic classification includes:

- "Nodular basal cell carcinoma" (also known as "classic basal-cell carcinoma") most commonly occurs on the sun-exposed areas of the head and neck.

- "Cystic basal cell carcinoma" is morphologically characterized by dome-shaped, blue-gray cystic nodules.

- "Cicatricial basal cell carcinoma" (also known as "morpheaform basal cell carcinoma," and "morphoeic basal cell carcinoma") is an aggressive variant with a distinct clinical and histologic appearance.

- "Infiltrative basal cell carcinoma" is an aggressive type characterized by deep infiltration.

- "Micronodular basal cell carcinoma" is characterized by a micronodular growth pattern.

- "Superficial basal cell carcinoma" (also known as "superficial multicentric basal-cell carcinoma") occurs most commonly on the trunk and appears as an erythematous patch.

- "Pigmented basal cell carcinoma" exhibits increased melanization. About 80% of all basal-cell carcinoma in Chinese are pigmented while this subtype is uncommon in white people.

- "Rodent ulcer" (also known as a "Jacob's ulcer") is a large skin lesion of nodular basal-cell carcinoma with central necrosis. Almost all cancers can metastasize except glioma (maligancy of the central nervous system) and the rodent ulcer.

- "Fibroepithelioma of Pinkus" most commonly occurs on the lower back.

- "Polypoid basal cell carcinoma" is characterized by exophytic nodules (polyp-like structures) on the head and neck.

- "Pore-like basal cell carcinoma" resembles an enlarged pore or stellate pit.

- "Aberrant basal cell carcinoma" is characterized by the formation of basal-cell carcinoma in the absence of any apparent carcinogenic factor, occurring in odd sites such as the scrotum, vulva, perineum, nipple, and axilla.

See also:

- Nevoid basal-cell carcinoma syndrome

Basal cell carcinoma makes up about 1–2% of vulvar cancer. These tend to be slow-growing lesions on the labia majora but can occur anywhere on the vulva. Their behavior is similar to basal cell cancers in other locations. They often grow locally and have low risk for deep invasion or metastasis.

Treatment involves excision, but these lesions have a tendency to recur if not completely removed.

Vaginal intraepithelial neoplasia (VAIN) is a condition that describes premalignant histological findings in the vagina characterized by dysplastic changes.

The disorder is rare and generally has no symptoms. VAIN can be detected by the presence of abnormal cells in a Papanicolaou test (Pap smear).

Like cervical intraepithelial neoplasia, VAIN comes in three stages, VAIN 1, 2, and 3. In VAIN 1, a third of the thickness of the cells in the vaginal skin are abnormal, while in VAIN 3, the full thickness is affected. VAIN 3 is also known as carcinoma in-situ, or stage 0 vaginal cancer.

Infection with certain types of the human papillomavirus ("high-risk types") may be associated with up to 80% of cases of VAIN. Vaccinating girls with HPV vaccine before initial sexual contact has been shown to reduce incidence of VAIN.

One study found that most cases of VAIN were located in the upper third of the vagina, and were multifocal. In the same study, 65 and 10% patients with VAIN also had cervical intraepithelial neoplasia and vulvar intraepithelial neoplasia, respectively.

In another study, most cases of VAIN went into remission after a single treatment, but about 5% of the cases studied progressed into a more serious condition despite treatment.

Sebaceous carcinoma is an uncommon and aggressive malignant cutaneous tumor. Most are typically about 10 mm in size at presentation. This neoplasm is thought to arise from sebaceous glands in the skin and, therefore, may originate anywhere in the body where these glands are found. Because the periocular region is rich in this type of gland, this region is a common site of origin. The cause of these lesions are, in the vast majority of cases, unknown. Occasional cases may be associated with Muir-Torre syndrome.

This type of cancer usually has a poor prognosis because of a high rate of metastasis.

Mucosal lentigines (also known as "labial, penile, and vulvar melanosis", and "melanotic macules") is a cutaneous condition characterized by light brown macules on mucosal surfaces.

Vulvar Paget disease presents as a variety of clinical lesions that may occur over a protracted course. Initially it is velvety, soft, and red or bright pink with scattered white islands of hyperkeratosis. (a strawberry and cream appearance) The lesions become erythematous, plaque like, and desquamating especially when located in dry areas. Rarely the appearance is ulcerated. The borders appear irregular, slightly elevated, and sharply demarcated. The visible borders of vulvar Paget disease are often misleading as Paget cells may spread along the basal layers of normal appearing skin with multicentric foci. Involvement may be extensive including the perianal region, genitocrural, and inguinal folds. Clinical examination should determine the presence of periurethral and perianal lesions. In these cases an involvement of the skin by a noncutaneous internal neoplasm may occur.

Symptoms are not specific; most patients report itching, burning, and soreness. A small subset of patients may be asymptomatic. Presence of vulvar pain, bleeding, and tumor formation are reported to be more common in patients affected by invasive disease.Signs and symptoms are skin lesions, often mistaken as eczema, that may be itchy or painful.

Granular cell tumor is a tumor that can develop on any skin or mucosal surface, but occurs on the tongue 40% of the time.

It is also known as Abrikossoff's tumor, Granular cell myoblastoma, Granular cell nerve sheath tumor, and Granular cell schwannoma.)

MCC usually presents as a firm, painless, nodule (up to 2 cm diameter) or mass (>2 cm diameter). These flesh-colored, red, or blue tumors typically vary in size from 0.5 cm (less than one-quarter of an inch) to more than 5 cm (2 inches) in diameter, and usually enlarge rapidly. Although MCC's may arise almost anywhere on the body, about half originate on sun-exposed areas of the head and neck, one-third on the legs, and about one-sixth on the arms. In about 12% of cases, no obvious anatomical site of origin ("primary site") can be identified.

Merkel-cell cancers tend to invade locally, infiltrating the underlying subcutaneous fat, fascia, and muscle, and typically metastasize early in their natural history, most often to the regional lymph nodes. MCCs also spread aggressively through the blood vessels, particularly to liver, lung, brain, and bone.

Vulvar childhood pemphigoid is a cutaneous condition, a childhood form of bullous pemphigoid, peculiar variant with involvement of the genital area and perineum.

The sarcoma first appears as a bruise mark, a purplish discoloration or a tender skin nodule in the extremity, typically on the anterior surface. It progresses to an ulcer with crusting, and finally to an extensive necrosis involving the skin and subcutaneous tissue. It metastasizes quickly.

Dermatofibrosarcoma protuberans can begin as a minor firm area of skin most commonly about to 1 to 5 cm in diameter. It can resemble a bruise, birthmark, or pimple. It is a slow growing tumor and is usually found on the torso but can also be found on the arms, legs, head and neck. About 90% of DFSPs are low grade sarcomas. About 10% are mixed; they contain a high-grade sarcomatous component (DFSP-FS); therefore, they are considered to be intermediate-grade sarcomas. DFSPs rarely lead to a metastasis (fewer than 5% do metastasise), but DFSPs can recur locally. DFSPs most often arise in patients who are in their thirties, but sometimes have been described in children or the elderly.

Bartholin gland carcinoma is an uncommon type of malignancy in the Bartholin gland that accounts for 1% of all vulvar malignant neoplasms. It is most common in women in their mid-60s. The tumor can become large before a woman is aware of symptoms. One of the first symptoms can be dyspareunia. In other instances a woman may find a mass or ulcer in the vulva area. Many clincians assume that an enlarged Bartholin gland is malignant in postmenopausal woman until proven otherwise. The growth of the tumor can spread to nearby areas such as the ischiorectal fossa and inguinal lymph nodes. Approximately 50% of bartholin gland carcinomas originate from squamous cell carcinomas. Another uncommon characteristic of Bartholin gland malignancies is that the growth of a lesion originates from the three types of epithelial tissue present in the gland: mucinous, transitional, and squamous.

Granular cell tumors show similarity to neural tissue, as can be demonstrated by immunohistochemistry and ultrastructural evidence using electron microscopy.

Multiple granular cell tumors may seen in the context of "LEOPARD syndrome", due to a mutation in the "PTPN11 gene".

These tumors on occasion may appear similar to neoplasms of renal (relating to the kidneys) origin or other soft tissue neoplasms.

Bartholin gland can be differentiated by histology to determine whether the malignancy is due to squamous cell carcinoma, adenoid cystic carcinoma, or adenocarcinomas.

Well-differentiated and moderately differentiated sebaceous carcinoma tend to exhibit vacuolization within the cytoplasm of the tumor cells. Histology may mimic basal cell carcinoma.

A urogenital neoplasm is a tumor of the urogenital system.

Types include:

- Cancer of the breast and female genital organs: (Breast cancer, Vulvar cancer, Vaginal cancer, Cervical cancer, Uterine cancer, Endometrial cancer, Ovarian cancer)

- Cancer of the male genital organs (Carcinoma of the penis, Prostate cancer, Testicular cancer)

- Cancer of the urinary organs (Renal cell carcinoma, Bladder cancer)

Lymphangiosarcoma is a rare malignant tumor which occurs in long-standing cases of primary or secondary lymphedema. It involves either the upper or lower lymphedematous extremities but is most common in upper extremities. Although its name implies lymphatic origin, it is believed to arise from endothelial cells and may be more accurately referred to as angiosarcoma.