From - juniper - hyster sister
there have been 12 recorded cases in the past (i think) 60 years of hysterectomies of women getting pregnant after surgery (there were 24 other cases of women having an ectopic before the surgery that was not discovered at that time).
A pregnancy would result from a tear in the vaginal cuff or if she kept her cervix in the cervical pouch.
An ectopic pregnancy can occur anywhere in the abdomen, though the most common place is in the fallopian tubes. A full-term pregnancy cannot be supported outside the uterus, the mechanism for supplying blood to the fetus just isn't there.
I hope this woman is able to find the proper medical care for whatever condition she might have (sometimes ovarian cysts can mimic pregnancy, causing lactation and positive pregnancy tests via urine analysis).
Take care.