Benign cystic mesothelioma of the appendix presenting in a woman: a case report

Our plain-English summary of Benign cystic mesothelioma of the appendix presenting in a woman: a case report, by D.B. O'Connor, D. Beddy, M.A. Aremu (Journal of Medical Case Reports, 2010).

The study

• Authors: D.B. O'Connor, D. Beddy, M.A. Aremu
• Journal: Journal of Medical Case Reports
• Published: 2010;4:394
• Cited by: 9 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Introduction: Benign cystic mesothelioma or peritoneal inclusion cysts are rare benign abdominal tumors usually occurring in females of reproductive age. These cysts present as abdominopelvic pain or masses but are often found on imaging or incidentally at surgery. They are commonly associated with pelvic inflammatory disease, endometriosis, or ovarian cysts. We report what is, to the best of our knowledge, the first case of a benign cystic mesothelioma complicating a presentation of acute appendicitis.

Case Presentation: A 19-year-old Irish Caucasian woman presented with abdominal pain. Imaging suggested appendicitis with abscess formation. She was treated with antibiotics and scheduled for interval appendicectomy. At laparoscopy, an unusual cystic mass was found arising from the appendix. Histology revealed benign cystic mesothelioma.

Conclusion: We report what is, to the best of our knowledge, the first case of a benign cystic mesothelioma arising from the appendix and complicating a presentation of acute appendicitis. This is a benign pathology, but recurrences are not uncommon. Benign cystic mesothelioma should be included in the differential when investigating pelvic masses or abscesses associated with either appendicitis or pelvic inflammatory disease in women.

In plain English

This article was a case report about one patient: a 19-year-old Irish Caucasian woman treated at St Vincent's University Hospital in Dublin. The authors described benign cystic mesothelioma, also called peritoneal inclusion cysts, as a rare benign tumor of unknown cause. The article does not mention asbestos or any other exposure. The woman came to hospital with three days of abdominal pain and fever. A CT scan showed a 10.4 × 4.5 × 3.8 cm cystic mass in the right pelvis that appeared to contain the tip of the appendix. A drain removed 30 ml of serous fluid but no pus. At a later operation, which the surgeons converted from laparoscopy to open surgery, they found a cyst joined to the tip of the appendix and removed it with the appendix. Microscope examination was consistent with a multiloculated benign cystic mesothelioma. The appendix showed resolving appendicitis with perforation at the tip. She was well at three-month follow-up. The authors concluded that this was the first reported case of benign cystic mesothelioma arising from the appendix and complicating acute appendicitis.

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 19-year-old Irish Caucasian woman treated by the Department of Surgery, St Vincent's University Hospital, Dublin, Ireland; the dates of treatment are not stated
• Exposure: The article does not mention asbestos or any other exposure. The authors described benign cystic mesothelioma as a benign tumor of unknown cause.
• Main results:
  • CT scan of the patient showed a 10.4 × 4.5 × 3.8 cm loculated cystic mass in the right pelvis that appeared to contain the tip of the appendix
  • An ultrasound-guided drain removed 30 ml of serous fluid and no pus
  • At laparoscopy, a smooth-walled cyst was found in continuity with the tip of the appendix; the surgeons converted to open surgery to remove the appendix and the cystic mass
  • The removed specimen was a 12-cm appendix with an attached 4 × 4 × 3 cm smooth cyst containing clear fluid
  • Histology was consistent with a multiloculated benign cystic mesothelioma
  • The appendix showed resolving appendicitis with perforation at the tip
  • The patient was well at six-week and three-month follow-up
• The authors' conclusion: The authors concluded that this was the first reported case of benign cystic mesothelioma arising from the appendix and complicating a presentation of acute appendicitis.

Topics

Medical terms in this study, explained in our Lexicon: Mesothelioma, Histology, Pathology.

Related studies

• Complicated benign cystic mesothelioma of mesoappendix misdiagnosed as an appendiceal abscess in a postpartum period woman — S. Yeom, T. Son, et al. (2015)
• Multicystic benign mesothelioma of the pelvic peritoneum presenting as acute abdominal pain in a young woman — J.H. Hong, S. Jeon, et al. (2013)
• Benign multicystic peritoneal mesothelioma presenting as a retroperitoneal pelvic mass in a young woman: a case report — E.A. Amaireh, O. Al-Natour, et al. (2026)
• Multicystic benign cystic mesothelioma presenting as a pelvic mass — M. Momeni, E. Pereira, et al. (2014)
• Intra-abdominal cystic lymphangioma of the mesocolon sigmoids: a rare entity in adult patient woman — A. Guachilema Ribadeneira, Á.R.T. Monard, et al. (2020)
• A Mesothelial Inclusion Cyst Presenting in a 40-Year-Old Woman as Abdominal Pain and Bloating - A Rare Diagnosis — S. Canadas, R. Fernandes, et al. (2020)

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