Gisser S D, Cortese B, diFlorio P E, Ances I G
J Reprod Med. 1985 Oct;30(10):789-91.
A 30-year-old white woman thought to have a 12-week intrauterine pregnancy developed a large cul-de-sac mass, which proved to be an ectopic, monoamnionic twin pregnancy (males) discordant for anencephaly. While twin pregnancies discordant for neural tube defects are well known, the extrauterine location made this case remarkable.
一名30岁的白人女性，原本被认为怀有12周的宫内妊娠，却出现了一个巨大的直肠子宫陷凹肿物，结果证实是一例异位单羊膜囊双胎妊娠（男性），双胎之一为无脑儿。虽然神经管缺陷不一致的双胎妊娠广为人知，但宫外的位置使该病例引人注目。
