Immunoglobulin G4-related disease in the stomach presenting as a gastric subepithelial tumor: Case report.

INTRODUCTION: Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated fibroinflammatory disorder characterized by specific pathologic findings and often, but not in all cases, elevated serum IgG4 concentration. Although it can virtually involve every organ system, cases involving the gastrointestinal tract and especially gastric mass lesions have rarely been reported.

PATIENT CONCERNS: A 45-year-old man, who was incidentally discovered asymptomatic subepithelial tumor (SET), by endoscopy, on the greater curvature of the upper gastric body, was referred to our hospital for further evaluation.

DIAGNOSIS: The patient was postoperatively diagnosed with IgG4-RD by histopathologic results.

INTERVENTIONS: The patient underwent laparoscopic wedge resection.

OUTCOMES: The patient is presently followed up annually in our clinic and had no problems and showed no signs of recurrence in examination.

CONCLUSION: We reported a rare case of IgG4-RD presenting as a gastric SET. The first line treatment of IgG4-RD is glucocorticoid administration. However, because pathologic examination is challenging owing to the lesion location, preoperative diagnosis is difficult and may lead to unnecessary gastric resection. Thus, using alternative preoperative diagnostic methods such as endoscopic ultrasound-guided fine-needle biopsy or the biopsy unroofing technique could spare the patient from unnecessary surgical treatment.