Gastric xanthogranuloma presenting as a small PET-avid gastric subepithelial lesion treated with laparoscopic and endoscopic cooperative surgery: a case report and literature review

Gastric xanthogranuloma is an extremely rare benign inflammatory lesion that can mimic a gastric subepithelial neoplasm. Preoperative diagnosis may remain difficult when imaging is suspicious and endoscopic ultrasonography-guided tissue acquisition is nondiagnostic. A 57-year-old man was referred for evaluation of a 15-mm gastric subepithelial lesion that was not visible on endoscopy performed 1 year earlier. Endoscopic ultrasonography showed a 15 × 9-mm hypoechoic lesion arising from the fourth layer, but fine-needle aspiration was nondiagnostic because of insufficient tissue. Contrast-enhanced computed tomography did not clearly depict the lesion. FDG-PET/CT, performed after EUS-FNA to assess the suspected gastric mesenchymal tumor and survey for other lesions, demonstrated intense uptake with a maximum standardized uptake value of 7.9. This finding was nonspecific and could not distinguish GIST from other mesenchymal or inflammatory lesions. Surveillance was discussed because of the small lesion size. After shared decision-making, the patient strongly preferred definitive diagnosis by local resection, and laparoscopic and endoscopic cooperative surgery was performed. Histopathology showed a submucosa-centered xanthogranulomatous lesion extending to the subserosa, with lymphoplasmacytic infiltration, CD68-positive foamy histiocytes, and fibrosis. The postoperative course was uneventful. Gastric xanthogranuloma should be considered in the differential diagnosis of PET-avid gastric subepithelial lesions. FDG uptake and SUVmax are not specific for GIST or malignancy, and short-term surveillance or repeat tissue acquisition may be reasonable in selected small, nondiagnostic lesions. When diagnostic uncertainty persists and local resection is ultimately selected after shared decision-making, LECS may represent an organ-preserving option for obtaining a definitive histopathological diagnosis.