[Intraabdominal foreign body caused diagnostic difficulty].

The problem of retained foreign body in the abdominal cavity following surgery is permanent and almost impossible to solve for abdominal surgeons. We present the story of a 49-year-old woman operated on because of a cystic lesion formed around a swab which was left in the abdominal cavity during open cholecystectomy ten years ago. We did not realise the nature of the lesion before the operation or by examination during the operation. The correct diagnosis was made after we opened the "lesion" after its removal.