Extragastrointestinal Stromal Tumor Presenting as Omental Cyst

Our plain-English summary of Extragastrointestinal Stromal Tumor Presenting as Omental Cyst, by A. Monabati, M. Safavi, F. Solhjoo (Journal of Gastrointestinal Surgery, 2016).

The study

• Authors: A. Monabati, M. Safavi, F. Solhjoo
• Journal: Journal of Gastrointestinal Surgery
• Published: 2016;20(6):1275-7
• Type of article: Case report
• Cited by: 14 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Introduction: Extragastrointestinal stromal tumors (EGIST) are rarer counterparts of gastrointestinal stromal tumors (GIST) in omentum, mesentery, and retroperitoneum.

Case Report: Hereby, authors present a 47-year-old man with abdominal mass whose abdominal CT scan revealed a large septated cystic mass measuring 16 cm in largest diameter. The mass was aspirated and resected by laparotomy. Pathologic examination exhibited a mesenchymal spindle cell neoplasm which was immunohistochemically reactive for CD117 and SMA. Thus, the diagnosis of extragastrointestinal stromal tumor was made.

Discussion: A cystic EGIST in omentum falls in the differential diagnoses of omental cystic lesions which include omental cyst, mesenteric teratoma, cystic mesothelioma, cystic spindle cell tumors, pseudomyxoma peritonei, pancreatic pseudocyst, and complicated ascites. Therefore, proper diagnosis of cystic GIST is of great importance in respect to different behavior, management, and complications in comparison to its mimickers and GI counterparts.

In plain English

This article is a case report describing one patient. It is about a rare tumor of the abdomen and does not discuss asbestos. A 47-year-old man had an abdominal mass, pain, nausea and vomiting after meals. A CT scan showed a large cystic mass with internal divisions in the left part of the abdomen, measuring 16×16×8 cm. Blood tests, including tumor markers, were in the normal range. At surgery the mass was found attached to the middle part of the jejunum (small intestine). Its fluid was drained, and the mass was removed along with 10 cm of nearby small intestine. Under the microscope the cyst wall was made of spindle-shaped cells. These cells tested positive for CD117 and smooth muscle actin and negative for S100 and desmin. The authors took this as confirming a cystic extragastrointestinal stromal tumor (EGIST) of the omentum. The tumor showed fewer than 5 dividing cells per 50 high-power microscope fields and no dead tissue. The authors listed cystic mesothelioma among the conditions such a mass can resemble. They concluded that cystic GIST should be considered when diagnosing cystic lesions of the omentum.

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
• Who was studied: One 47-year-old man with an abdominal mass, reported by authors from Shiraz University of Medical Sciences, Iran
• Main results:
  • CT scan showed a large cystic mass with internal divisions measuring 16×16×8 cm
  • Laboratory tests, including tumor markers, were in the normal range
  • The cyst fluid was aspirated and the mass was removed with 10 cm of adjacent small intestine
  • Tumor cells were positive for CD117 and smooth muscle actin (SMA) and negative for S100 and desmin, which the authors took as confirming a cystic omental EGIST
  • Mitotic count was less than 5 per 50 high-power fields, and no necrosis was present
  • The authors listed cystic mesothelioma among the conditions that omental cystic masses can be confused with
• The authors' conclusion: The authors concluded that omental cystic GIST should be considered in the differential diagnosis of omental cystic lesions and managed properly because of its different behavior and complications

Topics

Medical terms in this study, explained in our Lexicon: Omentum, Mesentery, Retroperitoneum, CT Scan, Laparotomy, Spindle Cell, Neoplasm, Mesothelioma.

Related studies

• CT-guided core-needle biopsy in omental pathology — F. Pombo, E. Rodriguez, et al. (1997)
• Surgical biopsy studies of omental and peritoneal nodules — D.B. Walsh, G. Williams (1971)
• Benign multicystic mesothelioma and peritoneal inclusion cysts: are they the same clinical and histopathological entities? A systematic review to find an evidence-based management — A.M.C. Rapisarda, A. Cianci, et al. (2018)
• Primary omental mesothelioma: a rare but important differential diagnosis in previous asbestos exposure — A. Harb, E. King, et al. (2010)
• Loose mesothelial cysts in the peritoneal cavity — Y. Ramirez, J. Rosai, et al. (2010)
• 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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