Multicystic peritoneal mesothelioma mimicking recurrent pseudomyxoma peritonei

Our plain-English summary of Multicystic peritoneal mesothelioma mimicking recurrent pseudomyxoma peritonei, by A. Scarton, M. Tonello, E. Pizzolato, et al (Journal of Surgical Case Reports, 2026).

The study

• Authors: A. Scarton, M. Tonello, E. Pizzolato, C. Cenzi, I. Cataldo, V. Mourmouras, P. Pilati, A. Sommariva
• Journal: Journal of Surgical Case Reports
• Published: 2026;2026(7):rjag525
• Type of article: Case report
• Read it: PubMed · Publisher · Free full text

Abstract

Multicystic peritoneal mesothelioma (MCPM) is a borderline variant of peritoneal mesothelioma with indolent behaviour but a significant recurrence rate without radical treatment. Due to its rarity, risk factors and optimal treatment are still to clarify. The present clinical case is a report of MCPM developed after laparoscopic cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (Lap CRS-HIPEC) for pseudomyxoma peritonei (PMP) of appendiceal origin. The patient was treated for PMP with Lap CRS-HIPEC. One year later a recurrence was suspected at the thorax-abdomen computed tomography scan. After multidisciplinary discussion, she underwent iterative Lap CRS-HIPEC. Pathological examinations revealed MCPM. After 3 years of follow-up the patient is disease-free for both tumours. This is a unique case of MCPM mimicking recurrent PMP. Lap CRS-HIPEC is an effective approach for both conditions.

© The Author(s) 2026. Published by Oxford University Press and JSCR Publishing Ltd.

In plain English

This case report described one woman, aged 56, treated at an oncology institute in Italy. After a splenectomy revealed low-grade pseudomyxoma peritonei (a mucus-producing tumour in the abdomen), she had keyhole (laparoscopic) surgery to remove the visible disease, followed by heated chemotherapy (Mitomycin C and Cisplatin) delivered into the abdomen. This combination is called Lap CRS-HIPEC. Pathology confirmed grade 2 pseudomyxoma linked to a low-grade tumour of the appendix. Almost a year later, scans showed pelvic fluid and cysts suspected to be the tumour returning. A second keyhole operation found grape-like, fluid-filled cysts but no mucus. The cysts were completely removed and heated chemotherapy was given again. Final pathology showed multicystic peritoneal mesothelioma, a borderline form of mesothelioma of the abdominal lining, not pseudomyxoma. The article reported she was free of both tumours after 3 years of follow-up. The article does not mention asbestos. The authors concluded that the two diseases looked alike on scans and during surgery. They suggested her previous surgeries and abdominal chemotherapy may have triggered the mesothelioma.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: case report (one patient)
• Who was studied: One 56-year-old woman seen at the Veneto Institute of Oncology IOV-IRCCS, Italy. She had a history of oestrogen receptor-positive ductal breast cancer (quadrantectomy, radiotherapy, 5 years of Tamoxifen), bilateral ovariectomy for a benign ovarian cyst, and a lung wedge resection for a benign lump. Dates of treatment are not given.
• Exposure: The article does not mention asbestos or any fiber exposure. The authors raised her previous surgeries and intraperitoneal chemotherapy (Mitomycin C and Cisplatin HIPEC) as possible triggers of the multicystic peritoneal mesothelioma.
• Main results:
  • At the first laparoscopic CRS-HIPEC (Mitomycin C and Cisplatin, 60 minutes, 41 degrees C), the peritoneal cancer index was 4. Pathology confirmed grade 2 pseudomyxoma peritonei with a low-grade appendiceal mucinous neoplasm.
  • After almost 1 year, CT showed pelvic free fluid and pelvic cysts suspected to be a recurrence. MRI confirmed the findings.
  • At the second laparoscopy, grape-like, fluid-filled cysts were found next to the uterus and cecum, with no mucin. Complete resection was achieved laparoscopically, and HIPEC with Cisplatin and Mitomycin C was given.
  • Final pathology showed a multicystic lesion without cellular atypia. It stained positive for calretinin and negative for Podoplanin, CD31 and CDX2. The diagnosis was multicystic peritoneal mesothelioma, which the article equates with multilocular peritoneal inclusion cyst in the WHO 5th edition terminology.
  • No complications occurred after the second operation, and the patient was discharged after 5 days.
  • After 3 years of follow-up the patient was disease-free for both tumours.
• The authors' conclusion: The authors concluded that this was a unique case of MCPM appearing after a diagnosis of PMP. In their view it showed how similar the two diseases are on imaging and during surgery. They wrote that previous surgeries and intraperitoneal chemotherapy may have triggered the MCPM, and that Lap CRS-HIPEC is an effective approach for both conditions.

Topics

Medical terms in this study, explained in our Lexicon: Peritoneal Mesothelioma, Cytoreductive Surgery, HIPEC, Thorax.

Related studies

• Long-term results of laparoscopic cytoreductive surgery and HIPEC for the curative treatment of low-grade pseudomyxoma peritonei and multicystic mesothelioma — F. Mercier, G. Jeremie, et al. (2020)
• The Delphi and GRADE methodology used in the PSOGI 2018 consensus statement on Pseudomyxoma Peritonei and Peritoneal Mesothelioma — R.J. Lurvink, L. Villeneuve, et al. (2021)
• Overall survival of pseudomyxoma peritonei and peritoneal mesothelioma patients after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy can be predicted by computed tomography quantified sarcopenia — A. Galan, P. Rousset, et al. (2018)
• Long-term outcomes and survival analysis of cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy in patients with pseudomyxoma peritonei at a newly established peritoneal malignancy centre in Japan — H. Yano, Y. Gohda, et al. (2024)
• Retroperitoneal approach for recurrent benign multicystic peritoneal mesothelioma — G.D. Bakhshi, K.R. Wankhede, et al. (2013)
• Malignant Peritoneal Mesothelioma Mimicking Recurrent Diverticulitis — E.S. Robalino Gonzaga, P. Guzman Rojas, et al. (2019)

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