Epithelioid and sarcomatoid malignant pleural mesothelioma in endoscopic gastric biopsies: a diagnostic pitfall

Our plain-English summary of Epithelioid and sarcomatoid malignant pleural mesothelioma in endoscopic gastric biopsies: a diagnostic pitfall, by A. Agaimy, P.H. Wünsch (Pathology, Research and Practice, 2006).

The study

• Authors: A. Agaimy, P.H. Wünsch
• Journal: Pathology, Research and Practice
• Published: 2006;202(8):617-22
• Type of article: Case report
• Cited by: 5 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Pleural malignant mesothelioma (MM) usually presents with chest pain, pleural effusion, or cough in middle-aged and elderly individuals with a history of asbestos exposure, but may rarely present at unusual metastatic sites. The luminal gastrointestinal (GI) tract is only rarely involved in patients with wide-spread disease at autopsy. Encountering MM in endoscopic GI biopsies is an exceptionally rare event in surgical pathology practice and may therefore pose great diagnostic challenges if not considered, in particular if the clinical history is not informative or the GI symptoms are the presenting signs of the disease. To our knowledge, only three cases of epithelioid mesothelioma (EM) involving the luminal GI tract (intestine) have been reported so far, but no case of sarcomatoid MM (SM) involving the GI mucosa has been described. We herein present the first two cases of MM (one each of EM and SM) of the pleura, presenting in endoscopic gastric biopsies as small polypoid lesions and poorly healing ulcers 30 and 35 months after the initial diagnosis of pleural MM, respectively. The major differential diagnoses encompass primary or metastatic adenocarcinoma in case one and cytokeratin-positive (KIT negative!) GI stromal tumors (GISTs) and sarcomatoid carcinoma in case two, as well as other rare entities.

In plain English

This teaching case report from Nuremberg, Germany, described two men whose pleural malignant mesothelioma was found in stomach biopsies taken during endoscopy. The first, a 79-year-old retired engineer with no sure history of asbestos exposure, had pleural fluid cytology highly suspicious for epithelioid mesothelioma, but no pleural tissue was taken. Thirty-five months later, small stomach polyps contained epithelioid tumor cells that stained for keratins, calretinin and other markers the authors use to identify epithelioid mesothelioma. He died a few days later, and his family declined an autopsy. The second, a 70-year-old worker with known occupational asbestos exposure, had a pleural biopsy showing biphasic mesothelioma. Thirty months later, poorly healing stomach ulcers showed a spindle-cell sarcomatoid tumor staining for keratins and vimentin. The authors knew of only three earlier English-language reports of epithelioid mesothelioma in the gut lining and none of the sarcomatoid type. They concluded that this rare event should be considered when unusual epithelioid or spindle-cell tumors appear in gastrointestinal biopsies, and that a wide marker panel is needed for diagnosis.

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 two patients (published as a teaching case), with a table comparing them to three previously reported cases
• Who was studied: Two men, aged 79 and 70, seen at the Nuremberg medical centre, Germany. Dates were not given.
• Exposure: Case 1 (79-year-old retired engineer): no sure history of asbestos exposure. Case 2 (70-year-old worker): known occupational asbestos exposure. Fiber types and doses were not reported.
• Main results:
  • Case 2 had known occupational asbestos exposure.
  • Case 1: pleural fluid cytology was interpreted as highly suspicious for epithelioid mesothelioma, but no pleural biopsy was taken.
  • Case 1: a gastric biopsy showed epithelioid tumor cells infiltrating the lining of the stomach between normal glands.
  • Case 1: the tumor cells stained strongly for several keratins, calretinin, thrombomodulin and EMA, among other markers.
  • Case 1: the patient died a few days after the gastric biopsies, and no autopsy was performed.
  • Case 2: the pleural biopsy showed a biphasic mesothelioma, mostly epithelioid with a small sarcomatoid focus.
  • Case 2: 30 months after diagnosis, biopsies from stomach ulcers showed a spindle-cell sarcomatoid tumor that co-expressed keratins and vimentin. Endosonography showed diffuse thickening of the stomach wall.
  • Case 2: immunostaining showed strong co-expression of keratins (KL-1, AE1/AE3, CK18) and vimentin, with focal SMA reactivity.
  • Across the authors' two cases and the three earlier reported cases, overall survival ranged from 8 to 84 months, with a mean of 41 months.
• The authors' conclusion: The authors concluded that mesothelioma involving the stomach or bowel lining should be considered when epithelioid or spindle-cell tumors with unusual features are found in gastrointestinal biopsies, and that a wide panel of positive and negative markers is needed for diagnosis.

Topics

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

Medical terms in this study, explained in our Lexicon: Epithelioid, Sarcomatoid, Pleural Mesothelioma, Malignant Mesothelioma, Pleural Effusion, Asbestos Exposure, Autopsy, Pathology.

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