A 71-year-old man with stage IV appendiceal mucinous adenocarcinoma remained recurrence-free for ten years, even though he never had HIPEC. His case is a reminder that survival is shaped by more than stage alone. Tumor biology, treatment decisions, and response to therapy all matter.

I read a lot of case reports. Most of them I file away. This one I wanted to share, because it gives real hope, and it shows how much there still is to learn.

A case report is the story of one patient. It is not proof of anything. But sometimes one story carries a lesson worth holding onto. This is one of those. Doctors in Japan published the case in the International Journal of Surgery Case Reports. On paper, this man’s diagnosis looked about as hard as it gets.

What happened in this appendiceal mucinous adenocarcinoma case

It started the way many of these stories do. He had pain in the lower right side of his belly. Doctors thought it was appendicitis and gave him antibiotics. Then his appendix ruptured, and he needed emergency surgery to remove it.

The pathology came back as appendiceal mucinous adenocarcinoma. There was cancer at the surgical edge, and the tumor carried several high-risk features. Over the next weeks his team ran more tests and did a second, larger surgery. They removed part of his colon, the nearby lymph nodes, and all ten tumor nodules they could see in his belly.

The final picture was stage IV. Cancer was in 6 of 12 nearby lymph nodes, and in one node farther away. It was graded G3, the most aggressive of the three tiers. A scan after surgery still suggested disease in his pelvis, so he started chemotherapy. He had capecitabine, oxaliplatin, and bevacizumab for about 13 months.

Then everything cleared. His scans went quiet. His tumor markers returned to normal. Ten years later, he remained recurrence-free. He did all of this without CRS/HIPEC, the surgery-plus-heated-chemotherapy that is the standard for this disease. HIPEC was not available at his hospital.

Can you survive stage IV appendiceal mucinous adenocarcinoma without HIPEC?

In rare cases, yes. This published case describes a man with stage IV appendiceal mucinous adenocarcinoma who remained recurrence-free for ten years after surgery and chemotherapy, without CRS/HIPEC. His outcome is unusual, and it should not be read as evidence that HIPEC is unnecessary.

This case does not tell us what the average stage IV appendix cancer survival looks like. It tells us that long-term recurrence-free survival is possible in carefully selected patients.

One: his biology was on his side

When surgeons removed ten suspicious peritoneal nodules, only one contained metastatic cancer cells. The other nine contained mucin, the thick jelly this kind of tumor makes, without tumor cells. So the amount of active cancer was much smaller than the scans made it look.

There was a second surprise. The first pathology read described cells that looked like signet-ring cells, which usually signal aggressive disease. A closer look changed that. The cells were floating in mucin and were not actually invading tissue. They were reclassified as pseudo-signet-ring cells. Same picture at a glance, very different meaning.

Two: the right team made the calls

That closer look is the second lesson. His pathology was reviewed again, and the new reading changed the picture of his cancer. This happens more often than people realize. Appendix cancer is rare, and the fine details are easy to miss on a first pass.

His care was also decided by a team, not one person. Surgeons, medical oncologists, and pathologists worked through his options together, and they brought him into the choice. When HIPEC was not on the table, they built a plan around the disease he actually had. If you take one action from his story, make it this. Ask for an expert pathology review, and ask to be seen by a team that treats appendix cancer often.

Three: the treatment matched the problem

His team removed every tumor they could see. Then they used chemotherapy to go after what a scan still showed. The surgery lowered the visible disease early, before more cancer could take hold. The chemotherapy appears to have controlled the remaining active disease.

It was not a smooth road. During chemotherapy he developed a blocked bowel and needed another emergency operation. He finished treatment anyway. The sequence worked for him, in his body, with his tumor.

Don’t overread this case

One patient cannot rewrite the standard of care. For pseudomyxoma peritonei, CRS/HIPEC remains the standard treatment for appropriately selected patients. Appendicure follows the 2025 Godfrey Consensus recommendations for appendix cancer. Other organizations, including NCCN, also publish guidance, and some details differ between guideline frameworks. The authors of this case reach the same practical conclusion: this patient’s remarkable outcome does not mean surgery without HIPEC should replace CRS/HIPEC.

His outcome could have looked very different with more active disease, faster-growing cancer, incomplete removal of visible disease, or a weaker response to chemotherapy. His case supports individualized treatment when HIPEC is not possible or not chosen. It does not replace the standard.

This case is about appendiceal mucinous adenocarcinoma with pseudomyxoma peritonei. It does not speak for every appendix cancer. Goblet cell adenocarcinoma, signet ring cell cancer, neuroendocrine tumors, and low-grade mucinous neoplasms are different diseases, and they follow different paths.

What keeps me thinking about this case isn’t that it breaks the rules. It’s that it reminds us how much we still don’t understand. Stage IV appendix cancer isn’t one disease, and two patients with the same diagnosis can have very different outcomes. That is exactly why we need better research, and why every patient’s story matters.

Source: Yamanaka Y, Kaizuka M, Ishimaru N, Yamashita T, Asano K. Ten-year recurrence-free survival in stage IV perforated appendiceal mucinous adenocarcinoma with high-risk features: a case report. International Journal of Surgery Case Reports, 2026. Read it here: https://doi.org/10.1097/RC9.0000000000000770

Common questions

Can you survive stage IV appendiceal mucinous adenocarcinoma without HIPEC?

In one published case report, a man remained recurrence-free for ten years after surgery and chemotherapy without CRS/HIPEC. HIPEC is still the standard of care for pseudomyxoma peritonei, and one case does not change that.

What is pseudomyxoma peritonei?

It is a condition where mucin-producing tumor cells spread inside the belly and build up jelly-like fluid. It often starts in the appendix.

Why does a second pathology review matter?

In this case, cells first read as signet-ring were later reclassified as pseudo-signet-ring cells. That reinterpretation suggested his tumor biology may have been somewhat more favorable than it first appeared. Appendix cancer is rare, and an expert second read can change the diagnosis.

Does one case report change treatment guidelines?

No. A case report is one patient’s story. It can raise good questions, but it is not proof. Guidelines still point to CRS/HIPEC for pseudomyxoma peritonei.

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