What was initially thought to be endometriosis in a 42-year-old woman turned out to be an extraordinarily rare form of cancer, necessitating the removal of nine organs in what doctors referred to as ‘the mother of all surgeries.’
Claire Gerring was referred to the renowned John Radcliffe Hospital in Oxford. Her symptoms, suggesting a condition where tissue resembling the uterine lining grows outside the womb, were first flagged during an ultrasound in November 2022. By May 2023, she was placed on the waiting list for a diagnostic laparoscopy.
However, Claire’s journey took a dramatic turn when she began experiencing severe pain on her right side. A faecal immunochemical test, designed to detect blood traces in stool, returned positive, prompting a colonoscopy.
During the procedure, doctors found her appendix was inverted, and further imaging through a CT scan showed malignant tissue was present. Urgent investigative surgery was immediately planned as a result.
By May 2025, a biopsy confirmed that Claire was suffering from stage four Pseudomyxoma Peritonei (PMP), a rare and aggressive cancer usually originating from an appendix tumor.
She was referred to Basingstoke and North Hampshire Hospital, one of only two hospitals that specialise in PMP.
The cancer in her appendix had ruptured, meaning there were other nodules in the rest of her body. In July 2025, Claire – mum to sons Oscar, 15, and Spencer, 14 – had a ten-hour operation to remove nine organs: her appendix, gallbladder, spleen, uterus, cervix and both ovaries and fallopian tubes.
She also had removed her greater omentum (a double layer of fatty tissue covering the lower abdominal area), belly button, peritoneum lining and part of her bowel. Her liver was also partially cut away, her diaphragm scraped and her bladder stripped.
Claire Gerring’s suspected endometriosis turned out to be a cancer so rare it required nine of her organs to be removed during ‘the mother of all surgeries’
In July 2025, Claire – mum to sons Oscar, 15, and Spencer, 14 – had a ten-hour operation to remove nine organs: her appendix, gallbladder, spleen, uterus, cervix and both ovaries and fallopian tubes
After four and a half weeks in hospital, she was discharged and has been left with bowel problems, but now has no evidence of disease. She will be monitored for the next 20 years.
Claire, a hairdresser from Wantage, Oxfordshire, says: ‘I felt really quite scared and quite alone after my diagnosis.
‘When you’ve got a rare cancer and it’s not something you’ve heard of before, there’s not a lot of people to talk to about it.
‘I was told by surgeons before my operation what they will remove. It’s a lot to process. It’s quite scary, but I’m lucky I had professionals who knew what they were doing. It’s called the mother of all surgeries because of the severity of it.’
She added: ‘Recovery is a slow process… if you have your appendix out the recovery time is six to eight weeks. I’m still grateful, it’s a small price to pay. Basically what they say is you’re never back to your old self, you just get used to the new you.’
Now a year into her recovery, Claire’s focus has turned to fundraising for charity Pseudomyxoma Survivor, throwing a masked ball last month.
On the night, she said: ‘I just feel my main purpose for doing this is raising awareness about the rare cancer and Pseudomyxoma Survivor. I feel so passionate about giving back to this charity who stepped in and helped me at the point in life when it felt uncertain and alone.’
‘They also support research and have recently given £100,000 towards a research project called ‘The Beacon Project’. They are creating a blood test to detect the cancer and recurrence way before CTs can even pick it up.’
She has raised £16,002 through Just Giving and other events.
Maddy Lomas, trustee at Pseudomyxoma Survivor, says: ‘We are incredibly touched by the effort and generosity behind this fundraising event. What makes it even more special is that it has been organised by someone who knows first-hand what it means to face a diagnosis of PMP.
After four and a half weeks in hospital, she was discharged and has been left with bowel problems, but now has no evidence of disease. She will be monitored for the next 20 years
‘Having received support from Pseudomyxoma Survivor during her own journey, Claire has now turned that experience into an opportunity to give back and support others who are walking a similar path.
‘For a small charity, the £16,002 raised is incredibly significant and will have a lasting impact.
‘For a rare disease like PMP, every person who learns about the condition helps to increase understanding and could make a life-changing difference by helping someone recognise the signs, seek support, or feel less alone following their own diagnosis.’