A Woman Lived with a 'Twin' Inside Her for 17 Years Without Knowing

A young woman in India unknowingly lived with one of the rarest and most unsettling m*edical conditions for nearly two decades, her doctors say. According to a case report out this week, the woman had a sac containing her still-growing “twin” lodged in her abdomen for 17 years.

The twin had hair, teeth, and even a spine.

Formally known as f*etus in fetu, the condition is thought to happen when one fetal twin gets enveloped by the other very early in pregnancy. The fetus doesn’t go on to develop its own nervous system and brain, but it’s still capable of living. And it sustains itself through its sibling, essentially becoming a parasite. Another theory holds that the second “fetus” is actually a complex form of t*umor called a teratoma; these tu*mors can develop different types of tissues at once, including hair and teeth.

Regardless of how the condition happens, it usually ends in misc*arriage, due to not enough nutrition available for the intact fetus. But even when someone survives, the condition is usually quickly detected soon after birth or in early childhood. Prior to this case, according to the woman’s d*octors, there had been only seven other reported cases of adults living with a fetal twin. And up until now, they had all been men.

The woman’s o*rdeal, detailed by her d*octors in BMJ Case Reports, really began five years before she visited them. That’s when she and her family first noticed she had a hard, mis*shapen l*ump around her abdomen.

Over the next five years, the l*ump gradually grew in size and caused her p*ain periodically. By the time the then-17-year-old visited the doct*ors, she wasn’t able to eat much before feeling full, likely because the l*ump had started to press on her internal organs.

On the initial physical e*xamination, the lump was s*uspected to be a t*umor. Which in a sense, it was. But when they ran a CAT scan on the lump, they found deposits of calcium that looked like “the shape of v*ertebrae, ribs and long bones,” and the more g*risly truth was finally uncovered. The d*octors then went to work removing it.

According to the report, the contents of the t*umor “consisted of hairs, mature bones and other body parts.” These body parts included “multiple teeth and structures resembling limb buds.” Its sheer size—36×16×10 centimeters—would also make it the largest ever found in a case of adult f*etus in fetu.

Thankfully, with the mass gone, the woman had a speedy and uneventful recovery, and two years later is still doing well.

“I am feeling very well and my abdomen is now flat and my parents are also very happy,” she wrote in a patient perspective included with the report.

The “twin” tumor, taken out of the girl’s body. Photo: Kumar, et al (BMJ Case Reports)