de Ruiter A, Carter P, Katz D R, Kocjan G, Whatrup C, Northover J, Mindel A
Academic Department of Genito-Urinary Medicine, University College London Medical School, UK.
Genitourin Med. 1994 Feb;70(1):22-5. doi: 10.1136/sti.70.1.22.
Anal intraepithelial neoplasia (AIN), which may be a precursor of anal carcinoma, has been identified on histology following minor anal surgical procedures, in particular the removal of perianal condylomata, in increasing numbers of homosexual and bisexual men. Anal cytology has recently been proposed as a useful method of identifying AIN lesions.
To compare anal cytology with histology as a method of detecting AIN.
215 homosexual and bisexual men attending a central London sexually transmitted diseases clinic had an anal cytological smear performed under standard conditions. The perianal area and anal canal were then examined using a colposcope, and areas macroscopically suggestive of intraepithelial neoplasia were biopsied.
176 of the 215 patients were biopsied of whom 76 had AIN on histology. 154 of the 215 patients had an adequate anal smear of whom 46 and 85 had cytological features of both HPV and AIN, or HPV alone respectively. Including features of HPV alone as an abnormal smear, anal cytology, when compared with anoscopy and histology as the gold standard for diagnosing AIN, resulted in a sensitivity of 87.5%, a specificity of 16.3%, a positive predictive value of 37.4% and a negative predictive value of 69.6%. Restricting abnormal smears to those with features of both HPV and AIN resulted in a sensitivity of 33.9%, a specificity of 72.5%, a positive predictive value of 41.3% and a negative predictive value of 65.7%.
Anal cytology is a sensitive but nonspecific method of identifying patients with biopsy proven AIN if cytological features of HPV alone are included as abnormal smears. Specificity is improved by restricting abnormal smears to those with features of both HPV and AIN but this markedly lowers the sensitivity of the test. At present, anoscopy and histology are required in addition to anal cytology to differentiate between patients who simply have anal condylomata and those who also have AIN.
肛门上皮内瘤变（AIN）可能是肛门癌的前驱病变，在越来越多的同性恋和双性恋男性接受小型肛门外科手术后的组织学检查中被发现，尤其是在切除肛周湿疣后。肛门细胞学检查最近被提议作为识别AIN病变的一种有用方法。
比较肛门细胞学检查与组织学检查作为检测AIN的方法。
215名到伦敦市中心性传播疾病诊所就诊的同性恋和双性恋男性在标准条件下进行了肛门细胞学涂片检查。然后使用阴道镜检查肛周区域和肛管，并对宏观上提示上皮内瘤变的区域进行活检。
215名患者中有176名接受了活检，其中76名组织学检查显示患有AIN。215名患者中有154名肛门涂片合格，其中46名和85名分别具有HPV和AIN的细胞学特征或仅具有HPV的细胞学特征。将仅具有HPV特征作为异常涂片，与作为诊断AIN金标准的肛门镜检查和组织学检查相比，肛门细胞学检查的敏感性为87.5%，特异性为16.3%，阳性预测值为37.4%，阴性预测值为69.6%。将异常涂片限制为同时具有HPV和AIN特征的涂片，敏感性为33.9%，特异性为72.5%，阳性预测值为41.3%，阴性预测值为65.7%。
如果将仅具有HPV细胞学特征作为异常涂片，肛门细胞学检查是一种识别经活检证实患有AIN患者的敏感但非特异性方法。将异常涂片限制为同时具有HPV和AIN特征的涂片可提高特异性，但这会显著降低检测的敏感性。目前，除了肛门细胞学检查外，还需要肛门镜检查和组织学检查来区分单纯患有肛门湿疣的患者和同时患有AIN的患者。
