A Rare Case of Multilocular Mesothelial Inclusion Cysts of the Pericardium: Diagnosis, Treatment, Follow Up, with Comprehensive Review of the Literature

Our plain-English summary of A Rare Case of Multilocular Mesothelial Inclusion Cysts of the Pericardium: Diagnosis, Treatment, Follow Up, with Comprehensive Review of the Literature, by A. Shadmanian, K. Patel, E. Alács, et al (Journal of Personalized Medicine, 2025).

The study

• Authors: A. Shadmanian, K. Patel, E. Alács, H. Gavallér, S. Agocs, M. Bitay
• Journal: Journal of Personalized Medicine
• Published: 2025;15(11)
• Type of article: Case report
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Multilocular mesothelial inclusion cysts-also known as benign multicystic mesothelioma (BMM)-are rare, typically arising in the peritoneal cavity. Pericardial involvement is extremely uncommon and can pose diagnostic and therapeutic challenges due to their recurrent and infiltrative nature. Accurate diagnosis and surgical strategy are critical for management and recurrence prevention.

Methods: We present the case of a 36-year-old woman with a prior history of malignant melanoma who developed recurrent multilocular cystic masses of the pericardium. Initial imaging with echocardiography, cardiac magnetic resonance (CMR), and computed tomography (CT) revealed multilocular pericardial cysts. Surgical resection was performed under cardiopulmonary bypass (CPB), but complete excision was limited due to epicardial infiltration. Histopathology confirmed a benign mesothelial origin. One year later, recurrence prompted a second surgical intervention with total pericardiectomy and Gore-Tex patch reconstruction.

Results: Postoperative recovery was uneventful in both instances. Follow-up imaging at 6 and 12 months demonstrated no significant recurrence. Histological analysis confirmed benign cysts lined with mesothelial cells, positive for calretinin and WT-1. This represents one of the first documented living cases of pericardial BMM managed with staged surgery and total pericardiectomy.

Conclusions: Pericardial BMM is a rare, benign, but potentially recurrent lesion. In cases of extensive or recurrent disease, total pericardiectomy may offer definitive treatment. Multimodal imaging, histopathological evaluation, and personalized surgical planning are essential for effective management.

In plain English

This case report from the University of Szeged, Hungary, described a 36-year-old woman, previously treated for malignant melanoma, with multilocular mesothelial inclusion cysts of the pericardium (the sac around the heart), also called benign multicystic mesothelioma. Imaging showed fluid around the heart and a many-chambered cystic formation. In a first operation using cardiopulmonary bypass, surgeons removed many cysts, some of which had grown into the heart's outer surface. They achieved close to complete removal while keeping the pericardium. Tissue tests showed mesothelial-lined cysts, positive for calretinin and WT-1, without atypia, malignancy or melanoma cells. At one year the cysts had returned. A second operation removed the cysts and performed what the authors called a total pericardiectomy, from one phrenic nerve to the other plus the layer over the diaphragm; a Gore-Tex patch reconstructed the defect. Imaging up to 4 years later showed no significant recurrence. Only small cysts remained near the subphrenic pericardium; these were impossible to resect and were judged clinically insignificant. The authors concluded that total pericardiectomy may provide definitive treatment. The article does not report whether this patient had any asbestos exposure.

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 of a single patient, followed by a narrative discussion of previously published cases (labelled by the authors as a review of the literature)
• Who was studied: One 36-year-old woman with a history of malignant melanoma treated eight years earlier, treated at the University of Szeged, Hungary
• Exposure: The article does not report any asbestos or occupational exposure for this patient. Asbestos is mentioned only in the discussion, citing another publication, as often linked to benign cystic mesothelioma in the abdomen.
• Main results:
  • Before surgery, cardiac MRI showed a multilocular cystic formation suggesting a pericardial origin, without infiltration into heart muscle. Echocardiography showed a pericardial effusion of about 2.5 to 3.0 cm, and CT showed an effusion up to 30 mm thick.
  • At the first operation, performed under cardiopulmonary bypass, many cysts were excised with close to complete resection, and the pericardium was preserved.
  • On histology, the cysts were lined by a single layer of flattened to cuboidal mesothelial cells with no atypia or malignancy.
  • Immunohistochemistry was positive for calretinin and WT-1, supporting a mesothelial origin.
  • No malignant melanoma cells were identified using special immunostains.
  • At the one-year follow-up, chest CT confirmed recurrence of multilocular cysts involving the epicardium and pericardial space.
  • At the second operation, the cysts were completely removed. This was followed by what the authors call a total pericardiectomy: resection of the pericardium from phrenic-to-phrenic nerve and removal of the diaphragmatic pericardial layer. The resulting pericardial defect was reconstructed with a Gore-Tex prosthetic patch.
  • Follow-up imaging at 6 to 12 months and at 4 years showed no significant recurrence. Only small residual cysts remained near the subphrenic pericardium; these were impossible to resect and were deemed clinically insignificant.
• The authors' conclusion: The authors concluded that these pericardial cysts may recur after incomplete excision, and that total pericardiectomy may provide definitive treatment and prevent recurrence.

Topics

Medical terms in this study, explained in our Lexicon: Pericardium, Multicystic Mesothelioma (MCM), Peritoneal Cavity, Pericardial, Surgical Resection, Histopathology, Pericardiectomy, Mesothelial Cells.

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• Collagenous Spherulosis in Well-Differentiated Papillary Mesothelioma in a Female With Multilocular Peritoneal Inclusion Cysts — B. AbdullGaffar, L.G. Raman (2019)
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