Vulval intraepithelial neoplasia in pregnancy
Vulval intraepithelial neoplasia (VIN) is a term used for precan- cerous skin conditions affecting the vulva. There are two distinct types, a type associated with HPV infection (usual type or uVIN) and a rarer form related to chronic inflammatory skin conditions such as lichen sclerosis (differentiated or dVIN).
High-grade uVIN (VIN2 and VIN3) is also known as high-grade squamous intraepithelial lesion (HSIL) (46).uVIN is increasingly a problem of younger women and its incidence increased fourfold from 1973 to 2000 (47, 48). VIN causes symptoms in approximately 80% of cases, including pain, soreness, pruritus, and psychosexual dysfunction. Symptoms can be severe and protracted, causing a significant impact on quality of life. Disease can be unifocal or multifocal. Spontaneous regression of high-grade uVIN is uncommon in older women, but authors have suggested spontaneous regression occurs in pregnancy in approximately 40% of cases and less commonly in non-pregnant women under the age of 35 years (49).
Treatment is historically surgical, involving excision of involved vulval skin with a narrow surgical margin. Various medical treatments have been studied in small trials and case series, with current evidence suggesting that topical imiquimod is an effective treatment for high-grade uVIN with the potential for complete clearance of disease in 40-60% of cases (46). The risk of progression to cancer is uncertain, but large case series suggests that it is in the region of 16% if high-grade uVIN is untreated, and approximately 4% where disease has been previously treated surgically, usually associated with multifocal disease (50).
It is therefore often a dilemma whether uVIN should to be treated during pregnancy. Unifocal, high-grade VIN can usually be excised during the second trimester with acceptable morbidity, providing the lesion is relatively small and does not involve the important structures of the clitoris, urethra, or perianal region. Data on the use of medical treatments during pregnancy is sparse, and imiquimod and other topical medical treatments such as 5- flurouracil, cidofovir, bleomycin and dinitrochlorobenzene are contraindicated in pregnancy (46). The United States Food and Drug Administarion classifies the use of imiquimod during pregnancy as a class ‘C medication, where animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans (51).
It is not known if imiquimo d is excreted via breast milk after vulval application, and therefore caution should be observed regarding its use by nursing mothers.