Clinicopathological Characteristics of IgG4-Related Disease Involving Uterus and Abdominopelvic Lymph Nodes: A Case Report.

Immunoglobulin G4-related disease (IgG4-RD) is a systemic fibroinflammatory disorder that commonly affects multiple organs and may be misdiagnosed when presenting at atypical sites. We report an example of IgG4-RD involving the uterus and abdominopelvic lymph nodes and review the literature to clarify clinical, pathological and laboratory features. A 51-year-old female patient presented with prolonged menstruation and underwent PET/CT that revealed hypermetabolic masses in the uterus and multiple abdominopelvic lymph nodes, initially suggesting malignancy. She underwent a total hysterectomy and lymph node biopsy. Histopathology showed storiform fibrosis, obliterative phlebitis and dense lymphoplasmacytic infiltrates with abundant IgG4-positive plasma cells. Serum IgG4 and IgG levels were markedly elevated, supporting the diagnosis of IgG4-RD. Postoperative therapy with a regimen comprising dexamethasone, cyclophosphamide and bortezomib resulted in a substantial reduction in serum IgG4 levels, indicating effective disease management. This case report emphasizes the need to consider IgG4-RD in unusual anatomical locations, to enhance clinical awareness, and to apply comprehensive diagnostic criteria to improve patient outcomes.