Vulvar intraepithelial neoplasia

The term vulvar intraepithelial neoplasia (VIN) 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.

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ISSVD Classification

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 dystrophy, Bowen's disease, and Krausosis 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, non invasive]]
• Invasive disease (vulvar carcinoma)

Diagnosis

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.

Treatment

Popular treatment modalities include topical chemotherapy, carbon dioxide (CO2 ) laser ablation, and surgical excision. Cryotherapy, a loop electrosurgical excision procedure (LEEP), cavitron ultrasonic aspiration (CUSA), and interferon injections are additional treatment techniques that have been reported.

The usefulness of cryotherapy is limited owing to the inability to control the area of treatment precisely. It is not routinely recommended for the treatment of VIN. LEEP seems applicable for small lesions and is certainly more economical than the laser or CUSA, but limited literature support its efficacy. Likewise, CUSA and interferon require further study before they can be recommended as a standard treatment for VIN.

Topical chemotherapy

Topical treatments include 5-fluorouracil (5-FU), dinitrochlorobenzene, and bleomycin. 5-FU is the most widely used and studied agent. This approach results in considerable local irritation and is not consistently successful, most likely related to poor patient compliance. Six to 10 weeks of treatment is necessary, and patients begin to experience a severe inflammatory response after approximately 2 weeks. This response

The avoidance of surgery and minimal scarring are obvious advantages to this approach; however, neoplastic epithelium of hair-bearing areas may not be adequately treated because the superficial sloughing of 5-FU may spare the sebaceous ducts and hair follicles. This potential ineffectiveness combined with the frequent premature discontinuation of therapy leads the authors to conclude that topical treatment for VIN is of limited value. This modality is reserved for women who refuse or are unable to undergo other ablative or excisional therapies.

Laser ablation

Ablation with the CO2 laser is an effective option for diseased epithelium in non-hair-bearing areas, and there is cosmetic healing. Laser ablation is typically accomplished in the outpatient setting, and the extent of tissue destruction can be controlled precisely in experienced hands with colposcopic guidance. Disadvantages of laser therapy are its painful nature and prolonged healing time. No tissue is available for pathologic

Wide local excision

Because of the added expense and prolonged healing associated with the laser, the authors' preferred treatment modality is surgical excision in most instances. This treatment can frequently be accomplished in the office setting and provides a tissue specimen for pathologic review. Surgical excision can be diagnostic and therapeutic on select lesions. Several options are available for surgical excision. Specific details of surgical technique are beyond the scope of this article, and the interested reader is referred to a previous publication by the authors.

References

• Committee on Terminology, ISSVD: New nomenclature for vulvar disease. Int J Gynecol Pathol 1989;8:83.