A 7-year-old boy was brought to a dental college hospital in Chennai, India, complaining of swelling in his jaw. His parents were worried that it was cancer, according to a Saveetha Dental College news post, but the doctors found something else: a huge, bag-like mass filled with 526 tooth-like structures.

Yes, the boy had more than 500 teeth in his mouth.

Doctors noticed the lesion on a scan, finding that it was filled with small, hard structures. Not knowing what it was, surgeons pulled the 200 gram lesion out in full, then set to work cracking it open.

It took surgeons 5 hours to get all the teeth out, according to the hospital's news post on the incident. They laid out the miniature teeth—which ranged from 1 to 15 millimeters—in a spiral on a table. The pathologist called it "reminiscent of pearls in an oyster," according to the hospital.

This wasn’t the first time that this boy went to a hospital with complaints of swelling in his jaw. His parents noticed it at age 3, too, but he didn’t cooperate with doctors trying to investigate "as he was very young," according to the hospital. Four years later, the swelling had only grown in size.

The lesion is called a compound odontoma, a tumor where normal dental tissue goes a bit haywire. According to Saveetha Dental College, where the surgery took place, this is the first time so many small teeth have been reported in a single individual.