Gastric Plexiform Fibromyxoma Resected Using Nonexposed Endoscopic Wall-Inversion Surgery: A Case Report

Area of Science:

• Gastroenterology and Surgical Oncology
• Gastrointestinal Pathology

Background:

• Gastric plexiform fibromyxoma is an exceptionally rare submucosal tumor (SMT) of the stomach.
• Accurate preoperative diagnosis of gastric SMTs can be challenging, especially when biopsy specimens lack tumor tissue.

Observation:

• A 1-cm hypervascular gastric SMT with low echogenicity was identified in a 41-year-old female patient.
• Contrast-enhanced computed tomography showed arterial hypervascularity and continuous post-venous enhancement.
• Endoscopic ultrasonography revealed a hypoechoic pattern.

Findings:

• Immunohistochemical analysis confirmed the tumor as plexiform fibromyxoma, positive for D2-40 and α-smooth muscle actin, and negative for markers of malignancy like c-kit.
• Ki-67 proliferation index was low (1-2%).
• Nonexposed endoscopic wall-inversion surgery (NEWS) achieved complete tumor resection.

Implications:

• NEWS is a viable and effective endoscopic treatment for gastric SMTs smaller than 3 cm.
• This case highlights the importance of combined imaging and immunohistochemistry for diagnosing rare gastric neoplasms.
• Minimally invasive endoscopic surgery offers a safe alternative to traditional surgical resection for select gastric SMTs.