Xu LY, Lin YQ, Yao RY, Yang ML, Shen HF, Zhang GS. Poorly differentiated adenocarcinoma misdiagnosed as gastrointestinal stromal tumor: A case report. World J Gastrointest Oncol 2026; 18(8): 120791 [DOI: 10.4251/wjgo.v18.i8.120791]
Corresponding Author of This Article
Gao-Song Zhang, Associate Chief Physician, Department of Gastroenterology, The People’s Hospital of Xinchang, No. 117 Gushan Middle Road, Shaoxing 312500, Zhejiang Province, China. gsongz@163.com
Research Domain of This Article
Gastroenterology & Hepatology
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case-report
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Xu LY, Lin YQ, Yao RY, Yang ML, Shen HF, Zhang GS. Poorly differentiated adenocarcinoma misdiagnosed as gastrointestinal stromal tumor: A case report. World J Gastrointest Oncol 2026; 18(8): 120791 [DOI: 10.4251/wjgo.v18.i8.120791]
Li-Ying Xu, Department of Medical Administration, The First Affiliated Hospital of Zhejiang Chinese Medical University (Zhejiang Provincial Hospital of Chinese Medicine), Hangzhou 310006, Zhejiang Province, China
Yu-Qi Lin, The First Affiliated Hospital of Zhejiang Chinese Medical University (Zhejiang Provincial Hospital of Chinese Medicine), Hangzhou 310006, Zhejiang Province, China
Ri-Yan Yao, Mei-Lin Yang, Gao-Song Zhang, Department of Gastroenterology, The People’s Hospital of Xinchang, Shaoxing 312500, Zhejiang Province, China
Hua-Feng Shen, Department of Pathology, The People’s Hospital of Xinchang, Shaoxing 312500, Zhejiang Province, China
Co-first authors: Li-Ying Xu and Yu-Qi Lin.
Author contributions: Xu LY, Lin YQ and Yao RY contributed to manuscript writing and editing; Xu LY and Lin YQ contributed equally to this manuscript as co-first authors; Yao RY and Yang ML contributed to collection of clinical data; Shen HF contributed to analysis of pathological results; Zhang GS contributed to conceptualization and supervision. All authors have read and approved the final manuscript.
AI contribution statement: ChatGPT and DeepL were used during the preparation and revision of both the manuscript and the answering-reviewers document for English translation, language polishing, grammar improvement, and editorial refinement. Some text expressions were generated or refined with the assistance of these tools; however, AI tools did not participate in the design of the study, data collection, data analysis, interpretation of the results, clinical reasoning, or development of the conclusions. All AI-assisted text was carefully reviewed, corrected, and approved by the authors. The authors take full responsibility for the content, accuracy, integrity, and originality of the manuscript.
Informed consent statement: Informed written consent was obtained from the patient for publication of this report and any accompanying images.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
CARE Checklist (2016) statement: The authors have read the CARE Checklist (2016), and the manuscript was prepared and revised according to the CARE Checklist (2016).
Corresponding author: Gao-Song Zhang, Associate Chief Physician, Department of Gastroenterology, The People’s Hospital of Xinchang, No. 117 Gushan Middle Road, Shaoxing 312500, Zhejiang Province, China. gsongz@163.com
Received: March 9, 2026 Revised: April 9, 2026 Accepted: May 18, 2026 Published online: August 15, 2026 Processing time: 152 Days and 23.7 Hours
Abstract
BACKGROUND
Gastric submucosal tumors (SMTs) comprise a heterogeneous group of lesions arising beneath the mucosal layer, among which gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms. However, some epithelial malignancies with predominant submucosal growth or atypical endoscopic manifestations may closely mimic SMTs, creating substantial diagnostic difficulty and increasing the risk of misdiagnosis when tissue sampling is limited or histologic interpretation is challenging.
CASE SUMMARY
A 58-year-old woman presented with recurrent epigastric discomfort for 1 month. Gastroscopy revealed a 1.5-cm SMT-like lesion with surface erosion and blood on the posterior wall at the junction of the gastric body and antrum. Endoscopic ultrasound demonstrated a hypoechoic lesion apparently originating from the muscularis propria, and diagnostic endoscopic submucosal dissection biopsy showed spindle cell-like morphology, leading to an initial impression of GIST. However, postoperative examination of the surgical specimen, together with immunohistochemistry, established the diagnosis of ulcerative poorly differentiated adenocarcinoma with invasion into the deep muscularis propria and metastasis in 2 of 28 regional lymph nodes. The patient subsequently received five cycles of adjuvant chemotherapy with the SOX regimen and showed no evidence of recurrence at the latest follow-up.
CONCLUSION
Suspected GIST with erosion or ulceration requires multimodal evaluation to confirm diagnosis and exclude epithelial malignancy.
Core Tip: Gastric adenocarcinoma with predominant submucosal growth may closely mimic gastrointestinal stromal tumor. In this case, a small submucosal tumor-like gastric lesion with surface erosion and bleeding was misdiagnosed as gastrointestinal stromal tumor because endoscopic ultrasound suggested a muscularis propria-derived lesion and diagnostic endoscopic submucosal dissection biopsy showed spindle cell-like morphology. The final diagnosis of poorly differentiated adenocarcinoma was made after surgical resection. Small submucosal tumor-like lesions with mucosal abnormalities require multimodal evaluation, adequate tissue acquisition, and timely immunohistochemical assessment to reduce misdiagnosis.
