Doctors Discover Brain Inside Teen’s Ovary


Doctors got an unusual surprise when removing a tumor from a teenage girl in Japan — they discovered the mass had a brain and skull.

Credit: Masayuki Shintaku et. al., 2017

The 16-year-old girl was having surgery to remove her appendix when physicians discovered a tumor growing on her ovary. 

When doctors cut the growth out they found clumps of greasy matted hair and a brain-like structure that measured about three-centimeters and was covered by a thin plate of skull bone.

Upon further inspection, they realized that the brain mass was a smaller version of a cerebellum — the area that sits right beneath the brain’s two hemispheres.

One side of the mass appeared to be a brain stem, which is the area which usually attaches to the spinal cord.

What Causes Ovarian Teratomas?

Tumors which contain body part growths or foreign tissue which can include hair, teeth, cartilage, fat and muscle are called ovarian teratomas. It comes from the Greek word ‘teras,’ which means monster. And while this discovery was unusual, it is not uncommon. Nearly one-fifth of benign ovarian tumors are ovarian teratomas.

A large ovarian teratoma is seen. Courtesy: Hellerhoff, CC BY-SA 3.0

The exact cause of ovarian teratomas are still unknown, but scientists believe it happens when immature egg cells go rogue and begin randomly producing various body parts.  Brain cells are often found in ovarian teratomas, but Masayuki Shintaku at the Shiga Medical Centre for Adults in Japan, who studied this teen’s tumor, says hers was unusual because the brain cells started to organize themselves into proper brain-like structures. Shintaku added that the mini-brain was so developed it could transmit electric impulses between neurons, just like any normal functioning brain.

Symptoms of Teratomas

Brain confusion is common and can occur in women with this disorder. When the immune system of a woman with an ovarian teratoma classifies the brain cells in the ovary as foreign and attacks it, it also attacks cells in her real brain as well. This causes inflammation and neurological symptoms that can include personality changes, paranoid thoughts, confusion, agitation, seizures or memory loss. These symptoms can usually be stopped by simply removing the tumor.

Thankfully, none of those medical incidents happened to the unnamed 16-year-old girl featured in this story. Prior to having her ovarian teratoma tumor removed, the young woman didn’t experience any neurological symptoms at all. At press date, her tumor was removed without complications and she enjoyed a good recovery.

Ronke Idowu Reeves

Ronke Idowu Reeves is a writer and journalist who hails from Brooklyn, NY. Her news and entertainment stories have appeared on WABC-TV-New York, Fox News Channel, VH1, plus in Sundance Film Festival’s Sundance Daily Insider and People Magazine.