Primary Localized Peritoneal Malignant Mesothelioma Involving the Stomach and Transverse Colon: A Case Report

Our plain-English summary of Primary Localized Peritoneal Malignant Mesothelioma Involving the Stomach and Transverse Colon: A Case Report, by S.R. Ahn, J.H. Lee (The Korean Journal of Gastroenterology = Taehan Sohwagi Hakhoe Chi, 2025).

The study

• Authors: S.R. Ahn, J.H. Lee
• Journal: The Korean Journal of Gastroenterology = Taehan Sohwagi Hakhoe Chi
• Published: 2025;85(4):559-562
• Type of article: Case report
• Read it: PubMed · Publisher · Free full text

Abstract

We report a rare case of primary localized peritoneal malignant mesothelioma (PMM) involving both the stomach and the transverse colon. A 55-year-old male presented with right upper quadrant pain and a palpable abdominal mass. Imaging revealed a large tumor invading the stomach and colon, with suspected early lymph node involvement. Preoperative biopsy results were inconclusive, and surgery was performed under the suspicion of a liposarcoma or gastrointestinal stromal tumor. The patient underwent laparoscopic subtotal gastrectomy and right hemicolectomy. Histopathological examination confirmed epithelioid-type malignant mesothelioma with no lymph node metastasis. Immunohistochemical staining was positive for calretinin, Wilms tumor 1, and cytokeratin 5/6. There was no history of asbestos exposure. The patient was discharged on postoperative day 25 and remained recurrence-free at a 9-month follow-up. Localized PMM is extremely rare and challenging to diagnose preoperatively due to nonspecific symptoms and overlapping radiological features. While diffuse PMM carries a poor prognosis and limited treatment options, localized forms may benefit from complete surgical resection. In select cases, cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy has shown promise. This case highlights the importance of considering PMM in the differential diagnosis of abdominal tumors and pursuing complete resection whenever feasible.

In plain English

This article is a case report from Wonkwang University in Korea about one 55-year-old man with primary localized peritoneal malignant mesothelioma. This is a cancer of the abdominal lining that stays in one area rather than spreading across it. The patient had pain in the upper right abdomen and a mass that could be felt. Scans showed a 13 cm tumor involving the stomach and transverse colon. Biopsies taken during endoscopy showed only nonspecific inflammation, so surgeons operated while suspecting a liposarcoma or gastrointestinal stromal tumor. They removed parts of the stomach and colon laparoscopically and found a 14×11 cm mass. Tissue examination showed epithelioid-type malignant mesothelioma with no lymph node spread. A review of the patient's occupational and environmental history found no evidence of asbestos exposure. Hyperthermic intraperitoneal chemotherapy (HIPEC) was not given. The patient left hospital on postoperative day 25 and had no recurrence at 9 months. The authors concluded that localized tumors tend to have a more favorable prognosis when completely removed. They noted that follow-up was short-term.

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 55-year-old male patient treated at Wonkwang University Hospital, Iksan, Korea; dates of treatment not stated
• Exposure: No asbestos exposure was found on review of the patient's occupational and environmental history
• Main results:
  • CT showed a 13 cm subepithelial gastric mass invading the transverse colon
  • Endoscopic biopsies before surgery showed only nonspecific inflammation, so no definitive diagnosis was made before the operation
  • At surgery a 14×11 cm mass was found outside the bowel on the surface of the transverse colon, invading the stomach
  • Tissue examination showed epithelioid-type malignant mesothelioma
  • There was no lymph node metastasis, and staining was positive for calretinin, Wilms tumor 1 and cytokeratin 5/6
  • Staining was negative for c-kit and CEA
  • HIPEC was not given because the diagnosis was not known before surgery
  • The patient was discharged on postoperative day 25 after delayed recovery due to postoperative ileus
  • The patient remained recurrence-free at 9-month follow-up
• The authors' conclusion: The authors concluded that localized tumors tend to have a more favorable prognosis when complete resection is achieved, underscoring the importance of accurate diagnosis and timely intervention
• Limitations the authors state:
  • Follow-up was short-term

Topics

The National Library of Medicine indexes this study under subjects our site covers: Mesothelioma, Peritoneal mesothelioma, Stomach cancer.

Medical terms in this study, explained in our Lexicon: Mesothelioma, Biopsy, Epithelioid, Metastasis, Immunohistochemistry, Calretinin, Wilms Tumor 1 (WT-1), Cytokeratin 5/6.

Related studies

• Malignant peritoneal mesothelioma with lymph node metastasis that originated in the transverse colon — Y. Takehara, S. Endo, et al. (2014)
• Localized malignant pleural mesothelioma showing a thoracic mass and metastasizing to the stomach — H. Hayashi, K. Notohara, et al. (2010)
• Metastatic primary peritoneal malignant mesothelioma mimicking primary diffuse gastric carcinoma: a rare encounter in gastric biopsy — Y. Yang, D. Gunawardane, et al. (2017)
• Institutional learning curve of cytoreductive surgery and hyperthermic intraperitoneal chemoperfusion for peritoneal malignancies — P.M. Polanco, Y. Ding, et al. (2015)
• The role of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in the treatment of peritoneal carcinomatosis: a systematic review including evidence from Japan — T. Kitai (2021)
• Well-differentiated papillary mesothelioma: peritoneal implants are not always metastases in the presence of cancer — G.W. Irwin, A. Ervine, et al. (2014)

Browse return to medical research.