A case of laparoscopically removed foreign body granuloma due to surgical sponge (so-called gauzeoma) retained for 21 years

A 57-year-old woman was admitted to our hospital with a pelvic mass and a left ovarian tumor. Twenty-one years ago, she had surgery for torsion of the right ovarian teratoma with salpingo-oophorectomy and appendectomy. Two years ago, a pelvic mass was found on magnetic resonance imaging (MRI), which was suspected to be a foreign body granuloma, but she complained of no symptoms, so she was instructed to follow up. However, a left ovarian tumor was additionally found during her annual medical checkup and she was referred to our hospital.