Primary Peritoneal Mesothelioma Affecting the Greater Omentum That Mimicked an Omental Infarction: A Case Report

Our plain-English summary of Primary Peritoneal Mesothelioma Affecting the Greater Omentum That Mimicked an Omental Infarction: A Case Report, by J.C. Cravero, T. Yakubik, L. Wahab, et al (Case Reports in Oncology, 2024).

The study

• Authors: J.C. Cravero, T. Yakubik, L. Wahab, T. Giang, L.M. Lopez, M.G. Newman
• Journal: Case Reports in Oncology
• Published: 2024;17(1):596-601
• Type of article: Case report
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Introduction: Malignant peritoneal mesothelioma (MPM) is a rare cancer that is associated with asbestos exposure. The diagnosis can be difficult given the nonspecific nature of presenting symptoms and the presence of concomitant confounding findings.

Case Presentation: We report a 71-year-old male who presented with right lower quadrant pain and new-onset ascites. CT imaging of the abdomen/pelvis demonstrated omental stranding concerning for a possible omental infarction. Subsequent imaging showed persistent omental edema but no identifiable soft tissue mass. A biopsy of the omentum showed atypical mesothelial proliferation, but pathology was unable to determine if proliferation was a neoplastic versus reactive process. Surgical oncology performed a diagnostic laparoscopy that showed peritoneal studding of the omentum. Subsequent immunohistochemical staining of the omentum demonstrated preservation of BAP1 expression and loss of MTAP expression, consistent with peritoneal mesothelioma.

Conclusion: MPM is a rare and aggressive cancer with an overall poor prognosis. The diagnosis of MPM can be difficult based on the nonspecific clinical presentation, insufficient imaging and laboratory testing, and the presence of concomitant confounding findings, such as with this patient and his admitting diagnosis of omental infarction. This case demonstrates the importance of developing a broad differential while maintaining an awareness of heuristics that can influence clinical decision-making.

© 2024 The Author(s). Published by S. Karger AG, Basel.

In plain English

This case report described one patient, a 71-year-old man at Baylor Scott and White Medical Center in Temple, Texas, diagnosed with malignant peritoneal mesothelioma affecting the greater omentum. A first CT scan for right lower abdominal pain showed changes thought to be a possible omental infarction. The patient returned 12 days later with new abdominal fluid (ascites). Repeat imaging showed swelling but no definite masses, and fluid tests found no cancer cells. A first biopsy could not tell whether the mesothelial cells were reactive or cancerous because the sample was small. Laparoscopy later found multiple small omental masses, and staining showed intact BAP1 and loss of MTAP, which the authors said confirmed the diagnosis. The patient's history included asbestos exposure while working at a lumber mill at age 20, and restoration of convenience stores, one built before 1980. No fiber type was named. The patient was referred for heated intra-operative peritoneal chemotherapy, and no outcome was reported. The authors concluded the diagnosis is difficult and that the early impression of omental infarction acted as an anchoring heuristic.

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 71-year-old male patient at Baylor Scott and White Medical Center, Temple, Texas, USA. The date of care is not stated.
• Exposure: Asbestos exposure reported in the patient's history: employment at a lumber mill at age 20, and restoration of convenience stores, one of which was built prior to 1980. No fiber type, product or dose is given.
• Main results:
  • The first CT of the abdomen/pelvis showed omental stranding, greatest in the right lower quadrant, which raised concern for an omental infarction.
  • On readmission 12 days later with new-onset ascites, a repeat CT showed mesenteric and omental edema but no definite soft tissue masses.
  • Ascitic fluid studies showed a SAAG score less than 1.1, and cytology was negative for malignant cells.
  • The first omental biopsy showed mesothelial proliferation with mild atypia. Because of the small tissue sample, it could not be determined whether the cells were reactive or neoplastic.
  • Diagnostic laparoscopy showed peritoneal studding with multiple small masses of the omentum, and a 3 cm piece of omentum was sent for pathology.
  • In the omental tissue, the mesothelial cells showed intact BAP1 expression and loss of MTAP expression, described as concerning for MPM. In the discussion the authors described this as confirming the diagnosis.
  • The patient's laboratory results included an elevated CA 125 (100.2), elevated CRP (154.3), elevated ESR (98) and elevated GGTP (443), with negative CA 19-9 and normal CEA (1.1). Units are not given. The authors noted that CA 125 was not initially checked because of low suspicion for cancer.
  • The patient followed up with hematology/oncology for treatment with heated intra-operative peritoneal chemotherapy. No treatment outcome is reported.
• The authors' conclusion: The authors concluded that MPM is a rare and aggressive cancer with a poor prognosis. In their view it is difficult to diagnose because of nonspecific symptoms, insufficient imaging and laboratory testing, and an overall weaker association with asbestos. They wrote that the initial diagnosis of omental infarction served as an anchoring heuristic. They recommended early surgical consultation for biopsy and immunohistochemical staining when clinical suspicion is strong.

Topics

Medical terms in this study, explained in our Lexicon: Peritoneal Mesothelioma, Omentum, Asbestos Exposure, Confounding, Ascites, Biopsy, Atypical Mesothelial Proliferation, Pathology.

Related studies

• Secondary malignant peritoneal mesothelioma of the greater omentum after therapy for primary pleural mesothelioma — A. Gutzeit, C. Reischauer, et al. (2013)
• Primary malignant mesothelioma of the greater omentum: report of a case — Y.C. Liu, Y.L. Kuo, et al. (2004)
• Gray scale sonographic presentation of a mesothelioma of the greater omentum — J.M. Shah, D.L. King (1979)
• Primary omental mesothelioma: a rare but important differential diagnosis in previous asbestos exposure — A. Harb, E. King, et al. (2010)
• Surgical biopsy studies of omental and peritoneal nodules — D.B. Walsh, G. Williams (1971)
• Surface and bulk modifications of amphibole asbestos in mimicked gamble's solution at acidic PH — A. Pacella, P. Ballirano, et al. (2021)

Browse more research in Case Reports in Oncology, or return to medical research.