A 26-year-old woman with a history of asthma, appendectomy, and ovarian cyst presents to the ED with lower abdominal pain and vaginal bleeding. She denies any recent fever, vomiting, or vaginal discharge besides blood. She is sexually active with her husband; they use condoms.
Her pregnancy test comes back positive. A transvaginal image from a pelvic sonogram is shown here. The diagnosis is pseudosac with likely ectopic pregnancy.
The sonogram shows a sac in the uterus, but this is not a normal gestational sac or a normal pregnancy. The presence of a pseudosac means the pregnancy is likely elsewhere, or ectopic.
A pseudosac typically is located centrally, may fill the entire endometrial cavity, and lacks the “double ring” sign. True gestational sacs usually are slightly off-center and have a detectable double decidual sign and eventually develop an internal yolk sac, followed by an embryo.
Pseudosacs occur in about 10% of ectopic pregnancies and can lead examiners astray if they are identified as a sign of a normal pregnancy and are not seen as a potential red herring. Testing includes a pregnancy test, blood typing, a CBC, and a pelvic ultrasound.
Case and image courtesy of Brady Pregerson, MD