Answer to the Parasite Case of the Week 672: Enterobius vermicularis, disembodied uterus containing characteristic planoconvex (or “D-shaped”) eggs. Note the beautiful deep pink-orange color. I have seen E. vermicularis eggs a few times on cervical Papanicolaou-stained smears, and they always looked like this.
I provided the size of the eggs for those of you not used to looking at Pap smears. However, you can also estimate the size of the eggs based on the size of the background mature squamous epithelial cells, as they are about the same size.
As mentioned by Florida Fan, “There must be a wandering pin worm, hopefully the patient does not have ectopic salpingitis.” The typical location of the adult female is the large intestine and anus. However, she sometimes leaves the anus and may enter the female genitourinary tract, as was the likely case here.
Thanks again to Dr. Anna-Lee Clarke for donating this case!