Surgeons in the Spanish capital Madrid have removed a 25kg tumour from a woman's ovary during a two-hour surgery.
The tumour is one of just a handful of cases of giant tumours - where the tumour weighs more than 11.3kg. There are only five cases of giant tumours ever recorded in scientific literature.
Eduardo Cazorla, head of the obstetrics and gynaecology department at the Torrevieja Hospital, said this was the first time he had ever dealt with such a case.
The 47-year-old woman's abdominal area had been swelling for around a year when her GP refered her to hospital in Madrid.
Tests showed a mass in her abdominal area and through further exams, doctors confirmed the existence of a giant cystic tumour extending from the pubis to xiphoid (the lower portion of the sternum).
Surgeons performed a total hysterectomy and a double oophorectomy, which involved the removal of the womb, both ovaries and the patient's fallopian tubes.
There were no complications during the two-hour surgery and a later biopsy of the tumour showed it was benign.
Cazorla said: "[In my] 20-year career [I] had never dealt with a similar case. The complexity of this type of intervention is very high, considering the particularity of the size of the tumour."
After the tumour was removed, the problems it had caused, including abdominal compression, difficulty urinating, bowel problems, respiratory difficulties, sleep problems and trouble walking, all went away.
The patient was discharged from hospital after five days and after 20 days of bed rest, she had recovered completely.
Since the surgery, she has attended regular gynaecological examinations but there has been no sign of the tumour returning.
Despite being a huge and rare tumour, it is nowhere near the biggest. The largest tumour ever removed intact was a multicystic mass on the right ovary which weighed 137.6kg. It was removed from a patient in the US in 1991.