Large posterior vaginal cyst in pregnancy

A 20-year-old primigravida presented in labour with a mass protruding from her vagina during uterine contractions. The mass was a large tense cyst measuring 8×8 cm arising from the posterior vaginal wall. The cyst was present since puberty but increased in size during pregnancy. It collapsed following aspiration and uneventful vaginal delivery was conducted. Following delivery, the cyst was excised and vaginal wall repaired. On histopathology the cyst was identified as a Müllerian cyst. The patient recovered and remained asymptomatic on follow-up.