Enterobius vermicularis infection of the ovary

Enterobius vermicularis is an intestinal parasite, which may occasionally involve extraintestinal sites including the female genital tract. We report a rare case of ovarian involvement, which presented with chronic right iliac fossa pain in a 31-year-old woman. A transvaginal ultrasound scan was suggestive of a right adnexal dermoid cyst; however, histological examination of the subsequent salpingo-oophorectomy specimen showed an abscess containing viable E. vermicularis ova. E. vermicularis is the most prevalent human nematode worldwide. Its ova are ingested, larvae hatch and mature female worms journey to the perianal region where they lay eggs. Female worms may also migrate from the anus along the female genital tract. Although of low pathogenicity, complications such as infertility or peritonitis may arise.