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Case Reports
. 2024 Aug 9;16(8):e66491.
doi: 10.7759/cureus.66491. eCollection 2024 Aug.

Gastrointestinal Stromal Tumor (GIST) Masquerading as a Pancreatic Pseudocyst: A Rare Case Report

Sarthak Sharma  1 , Varun Shetty  1 , Iqbal M Ali  1
Affiliations
Case Reports

Gastrointestinal Stromal Tumor (GIST) Masquerading as a Pancreatic Pseudocyst: A Rare Case Report

Sarthak Sharma et al. Cureus. .

Abstract

Despite their relative rarity, gastrointestinal stromal tumors (GIST) are the most common type of mesenchymal tumor in the gastrointestinal (GI) tract. Here, we describe a rare case of a 62-year-old hypertensive female presenting with abdominal pain and a palpable mass, initially suspected to be a pancreatic pseudocyst based on radiological findings. Subsequent histopathological (HPE) examination following surgical resection revealed a large cystic lesion originating from the stomach, characterized as a malignant epithelioid GIST. Based on these findings and taking into consideration the symptomatology of the patient, the decision was made to post the patient for an upfront, open surgical exploration without pre-operative biopsy studies. Frozen section facilities were kept on standby considering the differential diagnosis. Since the frozen section revealed a gastric GIST, a decision was made to perform subtotal gastrectomy, followed by gastrojejunostomy (GJ) and jejunojejunostomy (JJ). In addition, the part of the cyst adherent to the left lobe of the liver was dealt with with a non-anatomical wedge resection. Immunohistochemical (IHC) analysis showed positivity for Cluster of Differentiation 117 (CD117) with negativity for Cluster of Differentiation 34 (CD34), Desmin, and Discovered On Gastrointestinal Stromal Tumors 1 (DOG-1). The tumor exhibited aggressive features, including high mitotic activity, i.e., >5/10 high power field (hpf), hemorrhagic areas, and infiltration into the liver parenchyma. The patient then received adjuvant imatinib-based chemotherapy and was maintained on strict follow-up.

Keywords: epithelioid; gastrointestinal stromal tumour(gist); mesenchymal tumors; rare; solid tumors.

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Conflict of interest statement

Human subjects: Consent was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.

Figures

Figure 1
Figure 1. Endoscopic ultrasound (EUS) image showing the cystic lesion in relation to the stomach (pseudocyst of the pancreas/gastric GIST)
White arrow: Superficial mucosal layer of the stomach, Orange arrow: Deep mucosa of the stomach, Blue arrow: Submucosal layer of the stomach, Yellow arrow: Muscularis propria of the stomach, Green arrow: Serosa of the stomach, Red arrow: a cystic lesion of size 10*12*10 cm with a wall thickness of 7 mm without any septations. The lesion appears to be related only to the serosal layer of the stomach.
Figure 2
Figure 2. CECT: abdomen and pelvis (axial and sagittal cuts) demonstrating a predominantly cystic lesion compressing the stomach and left lobe of the liver
A) Axial cut: CECT (Abdomen): Portal venous phase A large, well-defined, hypodense, uniformly cystic lesion of size 136*117*122 mm (white arrow) is seen arising from the body of the pancreas, causing severe compression of the gastric antrum. It is seen extending in the gastrohepatic ligament between the stomach and left hepatic lobe, showing a peripheral solid component. The pancreas appeared bulky, with no per-pancreatic fat stranding. No obvious communication was noted with the main pancreatic duct (MPD). B) Sagittal cut: CECT (Abdomen): Portal venous phase A fairly large cystic, hypodense lesion occupying the lesser sac was seen abutting and causing compression of the gastric antrum. It showed peripheral enhancement in relation to the left lobe of the liver, indicating a solid component; however, with preserved fat planes. There is no associated lymphadenopathy. Findings were suggestive of a pseudocyst of the pancreas or gastric GIST. CECT: Contrast-enhanced computed tomography
Figure 3
Figure 3. Gross pathology images
3A) Gross specimen showing the external surface of the cyst wall, stomach, and a part of the liver attached (black arrow). 3B) Section of a large, thick-walled cyst with irregular cyst wall thickness (red arrow) and the part of the unremarkable gastric mucosa (black arrow).
Figure 4
Figure 4. Histopathological (HPE) and immunohistochemical (IHC) staining images
A) Malignant tumor comprising pleomorphic epithelioid cells (red arow) having vesicular nuclei, prominent nucleoli at places, and increased mitosis with areas of necrosis. B) CD117 immunoreactivity in GISTs that is strongly and uniformly positive in a cytoplasmic pattern
See this image and copyright information in PMC

References

    1. Histopathology of gastrointestinal stromal tumor. Miettinen M, Lasota J. J Surg Oncol. 2011;104:865–873. - PMC - PubMed
    1. Gastrointestinal stromal tumor of the small bowel complicated by torsion: A case report. Yoshizawa JI, Shimizu T, Ikehara T, Fukushima K, Nakayama A. Int J Surg Case Rep. 2022;100:107761. - PMC - PubMed
    1. Gastrointestinal stromal tumors—a mini review. Gheorghe G, Bacalbasa N, Ceobanu G, et al. J Pers Med. 2021;11 - PMC - PubMed
    1. Gastrointestinal stromal tumors (GIST) related emergencies. Sorour MA, Kassem MI, Ghazal Ael-H, El-Riwini MT, Abu Nasr A. Int J Surg. 2014;12:269–280. - PubMed
    1. Gastrointestinal stromal tumors (GISTs): SEAP-SEOM consensus on pathologic and molecular diagnosis. Martin-Broto J, Martinez-Marín V, Serrano C, et al. Clin Transl Oncol. 2017;19:536–545. - PubMed

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