Gastric cancer in a patient with IgG۴-related disease: Importance of diligent interpretation of [۱۸F]FDG PET/CT

IgG۴-related disease (IgG۴-RD) is a systemic fibroinflammatory disorder that can involve multiple organs, including the retroperitoneum. We report the case of a ۵۸-year-old man with IgG۴-related retroperitoneal fibrosis (IgG۴-RPF) diagnosed a decade earlier and initially managed with corticosteroids and azathioprine. Over the years, he developed a range of symptoms that ultimately led to the diagnosis of gastric cancer following complaints of dyspepsia. This case underscores both the diagnostic value and limitations of [۱۸F]FDG PET/CT in IgG۴-RD, particularly its inability to reliably distinguish inflammation from malignancy. Although [۱۸F]FDG PET/CT is commonly used to monitor the inflammatory activity of IgG۴-RD, this case highlights its potential role in detecting concurrent malignancies. It also emphasizes the critical importance of vigilant screening and long-term follow-up in this patient population.

کلیدواژه ها:

Gastrointestinal malignancy ، Immune-related disease ، [۱۸F]FDG PET/CT ، Retroperitoneal fibrosis