vaginal intraepithelial neoplasia ( vain ) is a rare human papillomavirus ( hpv)-related premalignant condition , histologically diagnosed , characterized by dysplastic changes in the vaginal epithelium , without stromal invasion . it accounts for only 0.4% of female lower genital tract intraepithelial lesions , with an incidence from 0.2 to 2 per 100,000  women / year . the persistent high - risk hpv infection is considered the necessary condition for the development of vain . multiple sexual partners and early stage at sexual debut , smoking , and immunosuppression , increasing the likelihood of hpv infection , are described as further risk factors involved in the development of vaginal dysplasia . furthermore , the presence of previous or synchronous cervical dysplastic lesions , or a previous hysterectomy for hpv - related cervical invasive or preinvasive lesions , are believed to be associated to the development of vain . although the risk factors for vain are similar to those described for cervical intraepithelial neoplasia ( cin ) , its incidence appear to be 100-fold lower ; this is believed to be due to the lack of a vulnerable squamocolumnar junction in the vagina . additionally , it is speculated that hpv infection of the vagina occurs as frequently as in the cervix , but a lytic cell reaction in the vaginal epithelium enables the regression of lesions , in contrast to the characteristic latent infection in the cervix which causes persistent dysplasia . vain is typically diagnosed through a colposcopy - guided biopsy of suspicious areas after an abnormal referring pap smear , and the number of diagnosis has increased steadily over the recent years because of the widespread use of routine screening cytology tests . most of the authors classified vain into low - grade lesions ( mild dysplasia , vain 1 ) and high - grade lesions ( high - grade vaginal intraepithelial neoplasia [ hg - vain ] : vain 2 and vain3 , corresponding to moderate and severe dysplasia ) according to the depth of tissue involved . to our knowledge , extensive data on cervical or vaginal cytology leading to the diagnosis of hg - vain are not available in the literature and only 1 study analyzed the abnormal referring cytology as a potential risk factor for the development of vain , though involving also low - grade vain . in this study , we restricted the analysis only on hg - vain , since these lesions can be assumed as the true precursor of vaginal cancer . the aim was to analyze the correlation between the first diagnosis of hg - vain and previous cytological abnormalities on the referral pap smear . all the women with histological diagnosis of vain 2 and vain 3 consecutively referred to the gynecological oncology unit of the aviano national cancer institute ( aviano , italy ) from january 1991 to april 2014 were considered . only women with a cytological assessment on pap smear performed in the 3 months before the diagnosis were included in the analysis . women with synchronous patients were identified by searching our clinical databases , and the medical records of women fulfilling the study inclusion criteria were retrospectively analyzed in an observational cohort study . data obtained included information regarding pertinent medical and surgical history and sociodemographic characteristics of each woman . high - grade squamous intraepithelial lesions ( hsil ) and atypical squamous cells , can not rule out high - grade sil ( asc - h ) were considered major cytological abnormalities .  atypical squamous cells of undetermined significance ( ascus ) and low - grade squamous intraepithelial lesions ( lsil ) were considered  lesser abnormalities . the diagnosis of hg - vain was made through biopsy of suspicious areas detected on colposcopic examination . similarly , any cervical suspicious areas were biopsied to exclude the presence of synchronous preinvasive or invasive lesions of the uterine cervix . colposcopic examinations were performed and recorded accordingly to the 2011 revised colposcopic terminology of the international federation for cervical pathology and colposcopy . the colposcopies performed before the introduction of the 2011 international federation for cervical pathology and colposcopy terminology were revised accordingly . the  testing and fisher exact test were used , as appropriate , to evaluate associations . from january 1991 to april 2014 , 153 women referred to the gynecological oncology unit of the aviano national cancer institute ( aviano , italy ) were diagnosed with hg - vain for the first time . the mean age of these women was 45.2-years old ( sd    13.9 , range 1878 years ) . among them , 50 women showed synchronous cervical intraepithelial lesions histologically assessed or cervical invasive cancer and were excluded . similarly 16 women were occasionally diagnosed with hg - vain , without a referral pap smear and were not included in the analysis . the mean age in the study cohort was 54.2 years ( sd    12.8 , range 3178 years ) and , in particular , 57 women ( 65.5% ) were in postmenopausal status . tobacco use was reported in 21 women ( 24.1% ) and hiv infection was present in 2 cases ( 2.3% ) . previous diagnosis of hpv - related cervical disease ( cin , carcinoma in situ or invasive cancer ) was reported in 44 cases ( 50.6% ) . forty - four women ( 50.6% ) previously underwent hysterectomy ; in particular , hysterectomy was performed because of cin or invasive cervical cancer in 31 cases , endometrial cancer in 5 cases , and ovarian cancer in 1 case . clinical characteristics of the study population regarding the referral pap smear results , the abnormal colposcopic findings and the grade of vaginal lesions detected , are reported in table 1 . clinical , colposcopic , and histological characteristics of the study group ( n  =  87 ) major cytological abnormalities , as previously defined , were reported in 48 cases ( 55.2% ) ; the remaining 39 women were diagnosed with lesser cytological abnormalities . the referral pap smear results in correlation with the subsequent histological findings of vain are reported in table 2 . cytological correlation to histological findings in the study population among women diagnosed with hg - vain , the most frequent cytological abnormality on the previous pap smear was hsil ( 42 cases , 48.3% ) . however , the proportion of previous major cytological abnormalities and lesser abnormalities on the referral pap smear was similar ( 55.2% vs 44.8% , p  =  0.2 ) . in the whole cohort , 33 cases of vain 3 were found , among them , the proportion of women previously diagnosed with major cytological abnormalities was significantly higher than those previously diagnosed with lesser abnormalities ( 72.7% vs 27.3% , p conversely , in the 54 cases of women diagnosed with vain 2 , the proportion of women previously diagnosed with major cytological abnormalities and with lesser abnormalities was similar ( 44.4% vs 55.6% , p  =  0.3 ) . the clinical characteristics of the study cohort in correlation with the referring cytological abnormalities are reported in table 3 . clinical characteristics of the study cohort in correlation with the referring cytological abnormalities in postmenopausal women ( n  =  57 ) , referral pap smear results of major abnormalities were detected in 37 cases ( 64.9% ) , with lesser abnormalities in the remaining 20 cases ( 35.1% ) . the rate of major abnormalities was significantly higher in these women , compared to premenopausal women ( 64.9% vs 36.7% , p  =  0.02 ) . similarly , referral pap smear results of major cytological abnormalities were significantly more frequent in women previously treated with hysterectomy ( 70.8% vs 32.5% , p  <  0.001 ) . in particular , this difference was confirmed in the 31 women treated with hysterectomy for premalignant or malignant hpv - related cervical lesions compared to the remaining women ( 77.4% vs 42.8% , p  =  0.01 ) . considering only women treated with hysterectomy for non - hpv - related malignancies ( endometrial or ovarian cancer ) or benign conditions ( n  =  13 ) the difference in referral pap smear results of major and lesser cytological abnormalities were not significant ( 20.8% vs 7.7% , p  =  0.16 ) . in the 44 women with previous hpv - related cervical lesions ( cin or invasive cervical cancer ) , the rate of major abnormalities on referring pap smear was significantly higher ( 70.5% vs 39.5% , p  =  0.01 ) . hg - vain is a very rare and asymptomatic premalignant condition , diagnosed through colposcopy - guided biopsy after an abnormal pap test result . the true prevalence of this condition is actually unknown but , in the last decades , its incidence is increased because of the widespread use of routine screening cytology tests . the correlation between abnormal pap smear and cin has been investigated to an extent in the literature , but extensive data on cytological abnormalities leading to the diagnosis of hg - vain are lacking . to our knowledge , only 1 study analyzed the correlation between vain and the referring cytological abnormalities detected on pap smear , reporting a high - grade referral cytology in 89% of women diagnosed with vain 2 - 3 . in our cohort , considering all the women diagnosed with hg - vain , the proportion of major abnormalities and lesser abnormalities on the referral pap smear was similar . the most frequent cytological abnormality on the referral pap smear was hsil , but in 44.8% of the cases , the diagnosis of hg - vain was preceded by lesser cytological abnormalities . this datum appear to be of particular interest , mainly when compared to data regarding the correlation between cin and previous cytological abnormalities on referral pap smear : a high grade cervical dysplasia is preceded by major cytological abnormalities in most of the cases . obviously , the detection of an abnormal pap smear requires a subsequent colposcopy with an accurate examination of the entire lower genital tract . an accurate examination of the whole vaginal walls and vault must be performed , and a biopsy of all suspicious areas is mandatory , even when colposcopy is preceded by lesser cytological abnormalities . postmenopausal status and previous hpv - related cervical invasive or preinvasive lesions are well known risk factors for the development of hg - vain . the persistent high - risk hpv infection is considered the necessary condition for the development of hg - vain . therefore , women with a history of hpv - related disease of the lower genital tract are more likely to develop vaginal lesions . the potential progression of these lesions could determine severe dysplastic lesions of the vaginal epithelium leading to major cytological abnormalities on referral pap smear . a previous hysterectomy for hpv - related cervical invasive or preinvasive lesions is believed to be another important risk factor for the development of vain . few studies , regarding occasional detection of vain during the usual cytological follow - up in women who underwent hysterectomy for cervical malignancies , were performed . kalogirou et al conducted a study to determine the number of patients with cin3 of the uterine cervix , treated with hysterectomy , who subsequently developed vain . the authors tried to define whether the following development of vain could justify intensive vaginal cytological and colposcopic follow - up . in the entire study population of 993 hysterectomized women , 41 ( 4.1% ) developed vain , and the diagnosis was preceded by the detection of ascus pap smear in 42% of cases . however in this study , the authors considered both low grade and hg - vain together . they considered 123 women with cervical cancer treated with primary hysterectomy and , among them , 12 women ( 9.7% ) developed cytological abnormalities on the routine follow pap smears . mild dyskaryosis ( corresponding to lsil according to 2001 bethesda system classification ) was reported in 7 cases and severe dyskaryosis ( corresponding to hsil according to 2001 bethesda system classification ) in the remaining 5 cases . only 6 women had positive colposcopic findings , with subsequent diagnosis of hg - vain in 4 cases and invasive vaginal carcinoma in the remaining 2 cases . however also in this case , the authors did not correlate the grade of vaginal dysplasia with the previous cytological abnormalities . the role of routine follow - up with pap smear in women previously treated with hysterectomy for benign disease is currently on debate . previous studies reported a 0 to 0.46% of positive vault cytology , thus some authors assert that there is insufficient evidence to recommend routine vaginal smear screening in women after total hysterectomy for benign disease . the american society for colposcopy and cervical pathology and the american college of obstetricians and gynecologists do not recommend routine vaginal smear screening in women who have had a hysterectomy and who do not have a history of cin 2 , cin 3 , or cervical cancer . in our cohort , 13 women ( 14.9 % ) were diagnosed with hg - vain after a hysterectomy performed for non - hpv - related malignancies ( endometrial cancer or ovarian cancer ) or for benign conditions . however , 12 of them had a history of hpv - related cervical lesions conservatively treated before the hysterectomy . the only 1-remaining case could have had an undiagnosed hpv - related disease at the time of hysterectomy or could have acquired an hpv infection after the hysterectomy . this data remark the importance of the cytological follow - up in women after hysterectomy for benign disease , when risk factors for vain are identified . thus is the history of hpv - related disease of the lower genital tract , rather than hysterectomy itself , that has to be considered as a risk factor for development of hg - vain . among hg - vain , vain 3 is currently considered as the true precursor of vaginal cancer by some authors , since a significant rate of occult superficially invasive vaginal cancer is reported in histological specimens of women excised for this condition . for instance , hoffman et al considering only women excised for vain 3 , reported a 28% of occult invasive vaginal cancers , while the rate appear to be lower when vain 2 and vain3 are considered together ( 12% in a study by indermaur et al ) . in our cohort , considering only women with histological diagnosis of vain 3 , we detected major cytological abnormalities on the referral pap smear in most of the cases . however , ascus or lsil on referral pap smear can not exclude hg - vain , especially vain 2 . this findings remark the importance of an accurate colposcopic examination , involving also the vaginal walls , in all the women with any abnormality on pap smear , mostly when other risk factors ( such as postmenopausal status or history of hpv - related lesions of the lower genital tract ) are detected . in this study , we reported 87 cases of women with hg - vain , that is , a relatively large number , considering the low rate of this condition in the general population . moreover , all the colposcopies and vaginal biopsies and the subsequent histological evaluation were performed in a single institution , by the same gynecologists and by the group of pathologists of aviano national cancer institute , with particular expertise in gynecologic  oncologic disease . however , due to its retrospective nature , this study has a potential limitations , since the data collected are limited to those already reported in the medical charts . the data of this study could be useful for clinicians to provide an appropriate counseling to women with abnormal pap test . these results stress the importance of an accurate colposcopic examination in women with abnormal pap smear , not only to identify and treat premalignant lesions of the uterine cervix , but also to identify and treat high - grade dysplastic lesions of vagina , preventing the development of invasive cancers . colposcopic examination of vagina may be technically difficult , mainly in women after hysterectomy , since the lesions can develop deep in the vaginal cuff and could be not easily observed . thus , colposcopy should be performed by qualified gynecologists with particular expertise in the lower genital tract premalignant diseases .
abstractthe aim of this study was to analyze the correlation between the first diagnosis of high - grade vaginal intraepithelial neoplasia ( hg - vain : vain 2vain 3 ) and the cytological abnormalities on the referral pap smear.all the women with histological diagnosis of hg - vain consecutively referred to the gynecological oncology unit of the aviano national cancer institute ( aviano , italy ) from january 1991 to april 2014 and with a pap smear performed in the 3 months before the diagnosis were considered , and an observational cohort study was performed.a total of 87 women with diagnosis of hg - vain were identified . 
 major cytological abnormalities ( hsil and asc - h ) on the referral pap smear were significantly more frequent than lesser abnormalities ( asc - us and lsil ) in postmenopausal women ( 64.9% vs 36.7% , p  =  0.02 ) and in women with a previous diagnosis of hpv - related cervical preinvasive or invasive lesions ( 70.5% vs 39.5% , p  =  0.01 ) . 
 diagnosis of vain 3 was preceded by major cytological abnormalities in most of the cases ( 72.7% vs 27.3% , p  <  0.001).the diagnosis of hg - vain can be preceded by different abnormalities on referral pap smear . 
 major abnormalities are usually reported in postmenopausal women and in women with previous cervical hpv - related disease . 
 however , asc - us or lsil do not exclude hg - vain , especially vain2 . 
 an accurate examination of the whole vaginal walls ( or vaginal vault ) must be performed in all the women who underwent colposcopy for an abnormal pap smear , and a biopsy of all suspicious areas is mandatory .