Photos of a giant bladder stone that a young woman recently had surgically removed have doing the rounds on Vietnamese social media.

Several Vietnamese media outlets have been reporting on the case of a 34-year-old woman who showed up at the emergency room of Phu Binh General Hospital, in Thay Nguyen, complaining of severe pain in her abdomen. After running some tests, a CT scan revealed that the woman had a massive, round mass in her abdomen. She was scheduled for emergency surgery, and a stone over 10-cm-long and weighing 400 grams was extracted from her bladder.

The news reports don’t offer too much information about this case, but photos include a CT scan, as well as a medical nurse posing with the giant stone. It was obviously quite a rare sight at the hospital…

According to a 2014 case report in the Turkish Journal of Urology, giant vesical calculi weighing more than 100 gm are rare, with fewer than 85 cases reported in English over the years involving a stone over 100 grams. If confirmed, this 400-gram- stone definitely qualifies as a medical oddity.

This is far from the largest bladder stone ever recorded. Back in 2016, Chinese doctors reported the case of a 54-year-old man who had a massive 1,048-gram pelvic stone in his bladder. And that was only the largest bladder stone ever recorded in China.

Photos of the 34-year-old woman’s 400-gram bladder stone went viral in Vietnam over the last couple of days, with most users expressing their disbelief about the woman’s threshold for pain.

“I only had a little sand , but I was in excruciating pain. How was  this person able to endure the pain caused by this thing?” one person asked. Others wondered how she didn’t feel any pain before the stone got this large.

The reason why some people’s bodies tend to produce this type of unusual mineral deposits is yet unknown.