Wang QJ, Gao JN, Wu PT, Lu GR, Xu XZ. Moderately to poorly differentiated adenocarcinoma invading a leiomyoma: A case report. World J Gastrointest Oncol 2026; 18(6): 118708 [DOI: 10.4251/wjgo.v18.i6.118708]
Corresponding Author of This Article
Xian-Zuo Xu, Department of Gastroenterology, The Third People’s Hospital of Cangnan County, No. 188 Wenxin Road, Qianku Town, Cangnan County, Wenzhou 325000, Zhejiang Province, China. 13706653410@163.com
Research Domain of This Article
Gastroenterology & Hepatology
Article-Type of This Article
case-report
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Wang QJ, Gao JN, Wu PT, Lu GR, Xu XZ. Moderately to poorly differentiated adenocarcinoma invading a leiomyoma: A case report. World J Gastrointest Oncol 2026; 18(6): 118708 [DOI: 10.4251/wjgo.v18.i6.118708]
Qin-Jian Wang, Jia-Ni Gao, Ping-Ting Wu, Guang-Rong Lu, Department of Gastroenterology, The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University, Wenzhou 325000, Zhejiang Province, China
Xian-Zuo Xu, Department of Gastroenterology, The Third People’s Hospital of Cangnan County, Wenzhou 325000, Zhejiang Province, China
Co-first authors: Qin-Jian Wang and Jia-Ni Gao.
Author contributions: Wang QJ, Gao JN, and Wu PT contributed to manuscript writing and editing; Wang QJ and Gao JN contributed equally to this article, they are the co-first authors of this manuscript; Lu GR and Xu XZ contributed to conceptualization and critical revisions; and all authors have read and approved the final manuscript.
AI contribution statement: Regarding the writing process of the manuscript and the use of AI tools, I would like to make the following explanations: (1) During the writing process of the manuscript, I only used translation tools such as DeepL, and did not use AI tools such as ChatGPT; (2) The main body of the paper (abstract, introduction, materials and methods, results, discussion and conclusion) has not been generated using AI tools; (3) Only DeepL was used to translate and polish some sentences, without using AI tools to analyze data or assist in manuscript writing; (4) AI tools were not involved in the design of the research or the interpretation of the results; and (5) All images are real medical records of the patients and no images were generated using AI.
Supported by Wenzhou Science and Technology Bureau, No. Y20240207.
Informed consent statement: Written informed consent was obtained from the patient prior to the initiation of any medical interventions and data collection.
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: Xian-Zuo Xu, Department of Gastroenterology, The Third People’s Hospital of Cangnan County, No. 188 Wenxin Road, Qianku Town, Cangnan County, Wenzhou 325000, Zhejiang Province, China. 13706653410@163.com
Received: January 12, 2026 Revised: February 3, 2026 Accepted: March 17, 2026 Published online: June 15, 2026 Processing time: 148 Days and 15.1 Hours
Abstract
BACKGROUND
Gastric collision tumors, where neoplasms of different origins coexist, are exceptionally rare. A specific challenge arises when gastric adenocarcinoma directly infiltrates a pre-existing benign mesenchymal tumor. This study aims to evaluate the effectiveness and safety of endoscopic treatment for gastric collision tumors.
CASE SUMMARY
A 59-year-old male presented with a three-year history of recurrent abdominal bloating. Gastroscopy revealed a well-defined, 1.2 cm submucosal bulge in the gastric body, with a central depression. Endoscopic ultrasound showed a heterogeneous, hypoechoic mass originating from the muscularis propria. The patient underwent endoscopic submucosal dissection. Histopathological examination of the complete endoscopic submucosal dissection specimen revealed moderately-to-poorly differentiated adenocarcinoma infiltrating into a spindle cell neoplasm. Immunohistochemistry was crucial for confirmation: The carcinomatous component was positive for cytokeratin-pan, while the spindle cells were positive for smooth muscle actin and desmin, and negative for CD117 and discovered on gastrointestinal stromal tumor-1, confirming a leiomyoma. The final diagnosis was a collision tumor of gastric adenocarcinoma and leiomyoma.
CONCLUSION
This case highlights the critical value of a multimodal diagnostic approach: Endoscopic ultrasound can suggest the possibility of a complex lesion, but only comprehensive histology and immunohistochemistry on the completely excised specimen can establish the diagnosis. Recognizing this rare pathological entity is essential for accurate diagnosis and appropriate clinical management.
Core Tip: Gastric collision tumors featuring adenocarcinoma invading leiomyoma are extremely rare, posing diagnostic and therapeutic challenges. This case describes a 59-year-old male with recurrent abdominal bloating, diagnosed via a multimodal approach: Gastroscopy, endoscopic ultrasound, contrast-enhanced computed tomography, histopathology, and immunohistochemistry. Immunohistochemistry (smooth muscle actin, desmin positivity for leiomyoma; cytokeratin-pan positivity for adenocarcinoma) was pivotal for definitive diagnosis. Endoscopic submucosal dissection (ESD) achieved en bloc resection with uneventful recovery and no recurrence at 8-month follow-up. Notably, the benign leiomyoma may have constrained malignant invasion, facilitating ESD feasibility. This report underscores the necessity of comprehensive diagnostics and supports ESD as a minimally invasive option for localized lesions, warranting further research on the tumor-stroma interaction.
