Mass-forming immunoglobulin G4-related cholangitis with atypical pancreatic lesions: a case report of difficult diagnosis.

backgroundImmunoglobulin G4 (IgG4)-related disease (IgG4-RD) is a systemic immune-mediated fibroinflammatory disease that results in the tissue destruction of multiple organs. IgG4-RD is often underdiagnosed or misdiagnosed as malignant, infectious, or other inflammatory disorder. CASE PRESENTATION: We describe a 56-year-old woman presented with jaundice and weight loss. Radiological imaging showed common hepatic duct wall thickening and nodular lesions in the pancreas, which was highly suspicious of malignancy. However, she was contraindicated for biopsy; hence, the diagnosis of IgG4-RD was made based on her high serum IgG4 level, multiorgan involvement, and steroid response. The effect of steroid therapy was significant, although the disease relapsed during the maintenance treatment. The dosage of steroid was re-increased, and the patient was under close follow-up.

conclusionsThe diagnosis of IgG4-RD is challenging due to its diverse manifestations. Therefore, a careful systematic assessment is necessary to improve the accuracy of IgG4-RD diagnosis, and a close follow-up is important to monitor the disease development as well as adjust the treatment strategy accordingly.