Doctors Find a Tiny Brain Growing Inside a Teenager's Ovary

Surgeons in search of one patient’s appendix found a little more than they bargained for. The teenager’s ovaries bore two large cysts, one of which contained a miniature skull and a “well-formed” brain. The surgeons described their findings in the journal Neuropathology.

The 16-year-old girl had been diagnosed with acute appendicitis and was brought in for emergency surgery. But after cutting into her abdomen, the doctors found more problems: two cystic tumors, one roughly the size of a golf ball and the other as big as a baseball. They took note of the cysts’ location and size, then completed the girl’s appendectomy and stitched her back up. Remarkably, she recovered just fine and reported no symptoms.

Three months later, they opened her up again, this time to remove the tumors. Inside the large cyst were more gruesome surprises: clumps of hair, a thin, skull-like plate of bone, and a surprisingly organized brain-like object.

Familiar-looking structures found inside the mini-brain. Image Credit: Masayuki Shintaku et. al., 2017

The thought of a tumor full of hair or bone is hardly unheard of, although it is fairly unsettling. These teratomas (from the Greek téras, or monster) are what happens when reproductive cells go rogue. Under healthy circumstances, they’ll deploy and become an embryo, differentiating into various body parts, such as bones, organs, teeth, and hair. But sometimes they just start growing, all on their own, making monstrous spare parts nobody needs or wants. Teratomas are typically found on or near a person’s reproductive organs, and they’re usually harmless (aside from the nightmares).

The most common teratoma contents are hair, teeth, and tissue that would, in a real embryo, one day become part of the central nervous system.

What makes this case different is the sophistication of the brain tissue inside the teratoma. The teeny organ was pretty far along, and had even separated into parts similar to those found in a fully developed brain. 

The surgeons patched the patient up again and sent her on her way. Three years later, they attempted to check up to see how she was doing, but she didn’t respond. We can’t really blame her.