Epithelioid Subtype Gastrointestinal Stromal Tumors of Stomach in an Endoscopic Biopsy: A Potential Diagnostic Pitfall

Abstract

Background

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract with a broad morphological spectrum. Although epithelioid GISTs account for 20% of GISTs, their morphological features may pose a diagnostic pitfall for pathologists due to their morphological similarities to poorly differentiated adenocarcinoma and lymphoma.

Case Presentation

Herein, we report a 65-year-old male patient with gastric epithelioid GIST misdiagnosed as adenocarcinoma for four years. During this period, he was treated with chemotherapy combined with PD-L1 immunotherapy. The clinicians thought the treatments were effective. However, there was no significant change in tumor size. The patient’s clinical symptoms did not improve significantly as well. Finally, an endoscopic biopsy was performed again and gastric epithelioid GIST was confirmed in our hospital through morphology, immunohistochemistry, and whole-genome sequencing.

Conclusion

A broad morphological spectrum and diverse immunophenotypic changes of GISTs could represent a pitfall for pathologists. However, predisposed anatomical sites, morphology, and corresponding immunohistochemical markers are of great significance for the diagnosis of GISTs and the differential diagnosis from other diseases. On the other hand, clinicians should diagnose and comprehensively evaluate treatment effects based on the patient’s clinical symptoms and relevant laboratory examinations, instead of over-reliance on pathological diagnosis.

Keywords:

• gastrointestinal stromal tumors
• misdiagnosis
• poorly differentiated adenocarcinoma
• stomach

Abbreviations

GISTs, Gastrointestinal stromal tumors; CK-pan, pan-cytokeratin; EGISTs, extra-gastrointestinal stromal tumors; PEComa, perivascular epithelioid cell tumor; RTK, receptor tyrosine kinase; TK, tyrosine kinase; TKI, tyrosine kinase inhibitors.

Ethics Approval and Informed Consent

This study was approved by the Ethics Committee of Guiqian International General Hospital. Our institution approved the publication of the case details. Written informed consent has been obtained from the patient for the release of relevant clinical and imaging data from their cases, included consent for the publication of the case details.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors declare no conflicts of interest in this work.

Additional information

Funding

No funding was available to support this research.