[You can skip this post if "blood and guts" aren't your cup of tea.]
The human body is [WARNING, graphic pic] awesome. The picture is not clear enough, but the article mentions it's a 66-pound non-cancerous ovarian cyst [could be a serous cystadenoma (a benign cyst), or maybe a teratoma or dermoid cyst (mostly benign cyst)].
Dermoid cysts are just cool [WARNING, all links are graphic]:
uterus with dermoid, and fibroids
toothy dermoid (blue arrow)
X-ray of 4 teeth inside a dermoid
Review of ovarian cysts (medspeak, but a good article)