Rose Marie Bentley lived most of her life in a rural Oregon town where she and her husband owned and operated a local feed store. In her small town, she sang in the choir, taught Sunday School, and loved to garden. On the outside, her life seemed one of normalcy – that is, until her recent death.

Bentley had a very extraordinary secret that was unbeknownst to her and her family for nearly a century.

After having donated her body to the Oregon Health & Science University, medical students soon found that the 99-year-old woman lived her entire life without knowing she had a condition called situs inversus with levocardia – a rare medical abnormality where her liver, stomach, and other abdominal organs were transposed right to left, but her heart remained on the left side of her chest. Literally, her internal organs (minus her heart) mirrored those of a normal human.

“I knew something was up, but it took us a while to figure out how she was put together,” said gross anatomy instructor Cam Walker in a statement. 

The extremely rare condition occurs just once in around 22,000 live births, or less than 0.0045 percent of the population. But those who make it to adulthood? Even fewer. Walker estimates only one in 50 million born with this specific condition will live to be adults as it can result in life-threatening concerns such as congenital heart defects. However, some like Bentley may have no associated health concerns if organ symmetry is normal and the condition is isolated. Medical literature reports only two other known survivors of isolated levocardia and situs inversus who have lived into their 70s, who were formerly believed to have been the oldest.

Bentley also had an abnormality called a hiatal hernia, which is when the upper bit of the stomach protrudes through the diaphragm. Additionally, her superior vena cava (SVC) vein was unusually long. Instead of collecting deoxygenated blood from the head, neck, and upper limbs, Bentley’s superior vena cava also collected deoxygenated blood from her rib cage wall and abdominal cavity. Her three liver veins also had their own unique function, draining directly into her heart’s right atrium instead of passing first through the inferior vena cava.

Despite all these abnormalities, Bentley’s family says that the woman didn’t have any other chronic conditions with the exception of arthritis. She had three organs removed including her appendix, which the operating surgeon noted as it having an abnormal location.

Bentley’s children were unaware of her unique body makeup and they believe she probably was too.

“My mom would think this was so cool,” said Bentley’s daughter Louise Allee, adding that her mother would have loved all of the attention her unique body is garnering. “She would be tickled pink that she could teach something like this. She would probably get a big smile on her face, knowing that she was different, but made it through.”

The team presented their findings over the weekend at this year’s gathering of the American Association of Anatomists at the Experimental Biology meeting.