A case of well-differentiated papillary mesothelial tumor concomitant with primary gastric cancer: case report and literature review

Our plain-English summary of A case of well-differentiated papillary mesothelial tumor concomitant with primary gastric cancer: case report and literature review, by G. Wang, P. Wang, C. Jiao (Frontiers in Oncology, 2026).

The study

• Authors: G. Wang, P. Wang, C. Jiao
• Journal: Frontiers in Oncology
• Published: 2026;16:1796106
• Type of article: Case report
• Read it: PubMed · Publisher · Free full text

Abstract

Background: Well-differentiated papillary mesothelial tumor (WDPMT) is a rare neoplasm characterized by low malignant potential. Due to the absence of distinct clinical symptoms, WDPMT is frequently detected incidentally during surgical procedures.

Case Description: This report describes a patient diagnosed with primary gastric cancer (GC) and concomitant WDPMT. The lesion was identified during laparoscopic radical gastrectomy and subsequently confirmed via histopathological and immunohistochemical analysis. No recurrence or disease progression was observed during a two-year postoperative follow-up period.

Conclusion: WDPMT remains a relatively rare disease. In addition to histopathological evaluation, immunohistochemistry and, where available, molecular genetic analysis contribute to diagnostic accuracy. However, conclusive evidence from large-scale studies are currently lacking. The overall prognosis of WDPMT is favorable, with surgical excision representing the standard therapeutic approach.

Copyright © 2026 Wang, Wang and Jiao.

In plain English

This article was a case report of one patient followed by a review of published literature on well-differentiated papillary mesothelial tumor (WDPMT), a rare mesothelial tumor of low malignant potential. A 65-year-old man had a 3.5 cm by 3.5 cm ulcerative stomach lesion found on routine screening, confirmed as gastric adenocarcinoma. During laparoscopic stomach surgery, surgeons found multiple soft tissue masses of about 1.0 cm on the greater omentum, the stomach surface and the peritoneum. Tissue examination and staining confirmed WDPMT. The stomach cancer was staged pT2N1M0 (Stage IIB), and he received six cycles of chemotherapy. No recurrence or progression was seen over two years of follow-up. The article did not report whether this patient had been exposed to asbestos. Discussing earlier studies, the authors wrote that peritoneal WDPMT lacks a documented link to asbestos, though a few pleural cases have been reported in people with asbestos exposure. The authors interpreted the two tumors occurring together as most plausibly coincidental. They concluded that the prognosis of WDPMT is favorable, with surgery the standard treatment.

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 with a literature review
• Who was studied: One 65-year-old man who had routine health screening on November 20, 2023 and was treated at the authors' hospital (980 Hospital, Shijiazhuang, China)
• Exposure: Not reported. The article gives no asbestos, occupational or environmental exposure history for this patient.
• Main results:
  • Endoscopy found an ulcerative lesion of about 3.5 cm by 3.5 cm in the gastric antrum. A biopsy confirmed gastric adenocarcinoma.
  • During laparoscopic radical distal gastrectomy, surgeons found multiple soft tissue masses, each about 1.0 cm, on the greater omentum, the serosal surface of the gastric body and the peritoneum.
  • Histopathology of the resected masses was consistent with WDPMT.
  • Immunohistochemistry was positive for calretinin, CK5/6, CK7, EMA and HBME1, and negative for CEA, ER and PR.
  • The gastric cancer had spread to 1 of 20 dissected perigastric lymph nodes.
  • The gastric cancer was staged pT2N1M0, Stage IIB.
  • The patient received six cycles of adjuvant XELOX chemotherapy (capecitabine and oxaliplatin) for the gastric cancer.
  • No recurrence or disease progression was seen over two years of follow-up after surgery.
  • From the literature discussion, not a finding of this case: peritoneal WDPMT lacks a documented link to asbestos exposure, although a few pleural cases have been reported in patients with a history of asbestos exposure.
  • The authors interpreted the occurrence of WDPMT together with the gastric cancer in this patient as most plausibly coincidental.
• The authors' conclusion: The authors concluded that the overall prognosis of WDPMT is favorable and that surgical excision is the standard treatment.
• Limitations the authors state:
  • BAP1 immunohistochemistry, which earlier literature suggested may be useful, was not part of the authors' department's protocol at the time of this case, so it was not done.

Topics

Medical terms in this study, explained in our Lexicon: Well-Differentiated, Stomach Cancer, Neoplasm, Disease Progression, Immunohistochemistry, Prognosis.

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