Rapamycin Treatment for Benign Multicystic Peritoneal Mesothelioma: A Rare Disease with a Difficult Management

Our plain-English summary of Rapamycin Treatment for Benign Multicystic Peritoneal Mesothelioma: A Rare Disease with a Difficult Management, by G. Stallone, B. Infante, L. Cormio, et al (The American Journal of Case Reports, 2017).

The study

• Authors: G. Stallone, B. Infante, L. Cormio, L. Macarini, G. Grandaliano
• Journal: The American Journal of Case Reports
• Published: 2017;18:632-636
• Type of article: Case report
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

BACKGROUND Benign multicystic peritoneal mesothelioma (BMPM) is a rare intra-abdominal tumor. Although considered by many to be benign, this tumor has a high local recurrence rate. Because of its rarity, preoperative diagnosis is difficult and its origin and pathogenesis are uncertain. There are no evidence-based treatment strategies for BMPM. It is agreed that the best treatment strategy for BMPM is the combination of surgical cytoreduction and hyperthermic intraperitoneal chemotherapy (HIPEC). An increasing body of evidence supports a pivotal role of the cytoplasmic serine/threonine kinase mTOR in the development and progression of several neoplastic diseases and specific mTOR inhibitors, including rapamycin, have been suggested as potential therapeutic options for different cancers. CASE REPORT A 65-year-old male with end-stage renal disease on hemodialysis for seven years presented with BMPM. He underwent surgery to remove multiple peritoneal cysts, but four months later he experienced a recurrence of the disease. Immunohistochemistry of the cysts demonstrated a high level of phosphorylation of p70S6 kinase, a downstream mTOR target, and since a target therapy that blocks PI3K/Akt/mTOR pathway has been shown to have a scientific and logical rationale to treat this rare intra-abdominal neoplasia, we started the patient on low dose rapamycin therapy, an mTOR inhibitor. Long-term mTOR inhibition resulted in a complete and stable remission of BMPM. CONCLUSIONS The current case is the first report of BMPM successfully treated with rapamycin, which resulted in a long-lasting response to mTOR inhibition.

In plain English

This was a case report describing one patient, treated by a nephrology unit whose authors are at the University of Foggia, Italy. The patient was a 65-year-old man with end-stage kidney disease who had been on hemodialysis for seven years. He had lost 20 kg over six months and had a large fluid-filled cyst in his abdomen. At surgery the doctors removed multiple cysts from the lining of the abdomen (the peritoneum), and laboratory tests confirmed benign multicystic peritoneal mesothelioma (BMPM). Four months later a new large cyst appeared, and the patient refused more surgery. Cells from the cyst showed signs that a cell-growth pathway called mTOR was active, so the authors treated him with low-dose rapamycin, a drug that blocks mTOR. After six months the cyst had shrunk and his abdominal pain had gone. After two years of treatment, a CT scan showed the cyst had completely disappeared. No side effects were reported. The authors concluded that rapamycin could be a logical option for treating BMPM. The article does not mention asbestos.

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 (single patient)
• Who was studied: One 65-year-old man with end-stage renal disease who had been on hemodialysis for seven years. He presented to the authors' division in April 2011. The authors' affiliations are at the University of Foggia, Italy.
• Exposure: No asbestos, occupational or environmental exposure is reported. The intervention was rapamycin, an mTOR inhibitor: a loading dose of 3 mg on the first day, then 1 mg/day targeting a blood trough level of 3–5 ng/mL, later lowered to 0.5 mg/day.
• Main results:
  • In this patient, histological and immunohistochemical tests on the removed peritoneal cysts were positive for mesothelial cell markers and calretinin, confirming BMPM.
  • Four months after surgery, a CT scan showed a new large peritoneal cyst in this patient.
  • Cells from this patient's cysts showed increased phosphorylation of p70S6 kinase, which is a marker of mTOR activation.
  • After six months of rapamycin, the cyst volume in this patient was reduced and his abdominal pain disappeared.
  • A CT scan after two years of treatment found the cyst had completely disappeared in this patient.
  • Rapamycin was well tolerated during follow-up and the patient had no side effects.
• The authors' conclusion: The authors concluded that rapamycin could be a logical option for treating BMPM. They described their report as the first case of BMPM successfully treated with rapamycin, with a long-lasting response.
• Limitations the authors state:
  • The authors stated that they could not determine whether the effect on cyst growth came only from blocking mesothelial cell proliferation, or from an effect of the mTOR pathway on cell polarity and secretion. They noted they lack reliable information on how the cysts form.

Topics

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

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• Benign multicystic mesothelioma and peritoneal inclusion cysts: are they the same clinical and histopathological entities? A systematic review to find an evidence-based management — A.M.C. Rapisarda, A. Cianci, et al. (2018)
• Laparoscopic diagnosis and treatment of pelvic benign multicystic mesothelioma associated with high CA19.9 serum concentration — V. Pinto, A.C. Rossi, et al. (2010)
• A rare case of benign multicystic peritoneal mesothelioma misdiagnosed as hydatid cyst found in the liver parenchyma and abdomen cavity of a male with asbestos exposure — A.B. Kelarji, M.S. Alshutaihi, et al. (2021)
• Imaging appearance of benign multicystic peritoneal mesothelioma: a case report and review of the literature — V. Mehta, V. Chowdhary, et al. (2017)
• A recurrence of benign multicystic peritoneal mesothelioma treated through laparoscopic excision: a case report and review of the literature — T.D. Witek, J.W. Marchese, et al. (2014)

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