IgG4-Related Disease, a Systemic or Local Disease: This is the Problem

Immunoglobulin G4-related disease (IgG4-RD) is a fibroinflammatory condition that forms tumefactive lesions in various organs, presenting with diverse clinical manifestations. Diagnosis of IgG4-RD could be challenging and relies on characteristic histopathological findings and elevated IgG4+ plasma cell counts.

The patientwas a48-year-old woman with diabetes mellitus initially presented with a painless breast mass. Imaging indicated irregular opacities and lymph nodes in the breast. Biopsy results revealed lymphoplasmacytic infiltration with IgG and IgG4 positivity, overall compatible with IG4-related disease. A mass resection was performed, and intraoperative assessment ruled out malignancy. Then,with a 5-month interval of no symptoms, the patient developed a cheek mass, initially misdiagnosed as low-grade spindle cell sarcoma. Subsequently, she underwent partial maxillectomy, further examination,and histology confirmed IgG4-RD, meeting all diagnostic criteria.

This case underscores the diagnostic challenges posed by IgG4-RD, often mistaken for malignancies due to its invasive behavior and emphasizes the importance of considering IgG4-RD in differential diagnoses for tumor-like lesions, particularly when affecting multiple organs, to enable timely treatment decisions and prevent unnecessary interventions.