Clinical findings in prepubertal girls with inguinal hernia with special reference to the diagnosis of androgen insensitivity syndrome

Abstract

Complete androgen insensitivity syndrome (CAIS) is a rare disease. However, there is a higher rate of CAIS in girls with inguinal hernia. The aim of this study was to estimate the incidence of CAIS in girls with inguinal hernia and to find a proper screening test for CAIS in these girls. A total of 109 consecutive girls attending the University Hospitals of Turku and Tampere, Finland, for inguinal hernia repair between January 2003 and December 2007 participated in the study. After induction of anaesthesia, vaginal length was measured with a small, lubricated Hegar dilator. During hernia repair, tension was placed on the round ligament to identify the contents of the hernial sac. The karyotype of all patients was measured, with identification of the Y-chromosome from a buccal mucosa swab sample. Vaginal length measurements were plotted against age and standards for vaginal length in prepuberty were established. Four patients were found to have very short vaginas, with one CAIS patient confirmed as having a 46XY karyotype from the verification of the Y-chromosome from buccal mucosa. The other three patients with abnormal vaginal length were karyotypically normal XX girls and had visible ovaries, fallopian tubes or round ligament, which suggests an error in the measurements. Unlike all the other operated girls, the CAIS patient lacked a round ligament. The incidence of CAIS in girls undergoing hernia repair was 1%. The CAIS patient had a significantly shorter vagina than girls with normal karyotype. Vaginal length is a useful additional clinical tool in screening girls for karyotyping CAIS, especially if abnormalities in the round ligament and contents of the hernial sac are suspected. It is recommended that ovaries and fallopian tubes are searched for if the round ligament is not found to be normal during the hernia operation. If no ovaries or fallopian tubes are found, consent for karyotyping should be sought in cases where the vaginal length is <4 cm in girls older than 4 years and <3 cm in younger girls.