A. There is a left para-aortic cystic mass with an enhancing wall. B-E. There is mildly increased FDG uptake in the wall of the mass, with SUV^max of 2.3.

Abdominal ectopic pregnancy was confirmed by a subsequent abdominal ultrasound revealing a viable abdominal gestation with gestational age of 8 weeks and 3 days.

An ectopic pregnancy occurs in approximately one out of 150 pregnancies, most commonly in a tubal location. Risk factors include pelvic inflammatory disease with chronic salpingitis, tubal adhesions due to previous surgery, appendicitis or endometriosis, and intrauterine contraceptive devices. Abdominal ectopic pregnancies occur rarely (1.3% of ectopic gestations), when the fertilized ovum drops out of the uterine tube, then follows usual development with formation of implantation site decidual reaction, amniotic sac, foetus and placenta. PET-CT has been used to detect primary choriocarcinomas in patients similar to our case, with increasing b-hCG and negative gynaecologic work-up. It has also been used to detect metastases in known gestational trophoblastic disease, with reportedly better accuracy than conventional imaging.