The 67-year-old patient was hospitalised with complications and high temperature after a flu. But doctors from the university obstetrics and gynaecology hospital in Sofia discovered that a giant mass was squeezing a number of vital organs.
"We removed a 23-kilo tumour, which is the size of a seven- or eight-year-old child," surgeon Bozhidar Slavchev said in a hospital statement.
"I have not seen such a bad case of neglected health in my entire long-time career," he added.
The woman told the doctors she had known about the tumour for some 20 years now but was afraid to undergo surgery.
"We have seen similar curious cases described in medicine textbooks from the beginning of the previous century, and it is worrying that today there are still patients who have not had prophylactic examinations for 20 years," another surgeon, Stefan Konstantinov, said.
The woman lost one third of her total weight after the operation.