Just a mirage: heterotopic intrauterine and twin ectopic pregnancy mimicked by mirror imaging on ultrasound.

Heterotopic pregnancies are rare and are usually diagnosed by transvaginal ultrasound. Despite the routine use of sonography in early pregnancy, artifact created by mirror imaging can drastically and erroneously alter medical decision making by interfering with image interpretation. A heterotopic pregnancy with a single intrauterine gestation and twin left adnexal ectopic gestational sacs was observed on ultrasound in a woman presenting with abdominal pain. During laparoscopy, an ectopic pregnancy was not identified, and subsequent intraoperative ultrasound reproduced the heterotopic pregnancy through manipulation of bowel, confirming mirror image artifact. This phenomenon is rarely seen in obstetric imaging; therefore, lack of awareness can lead to false diagnosis of heterotopic pregnancy. Techniques to verify correct diagnosis should be used to resolve potential mirror artifact before proceeding with surgical management.