Generalized gingival enlargement, periodontitis, and osteonecrosis of the jaw as manifestations of IgG4-related disease: A rare case report

Rationale:Immunoglobulin G4-related disease (IgG4-RD) is an immune-mediated systemic fibro-inflammatory condition involving one or multiple organs. We report a rare case of IgG4-RD associated with generalized gingival enlargement, periodontitis, and osteonecrosis of the jaw in a Chinese man.Patient concerns:A 44-year-old Chinese man visited the Department of Periodontology with gingival enlargement and increasing tooth mobility. He had previously undergone nonsurgical periodontal treatment and surgical periodontal treatment. However, his symptoms were not relieved.Diagnoses:The patient had extremely poor oral hygiene and a large amount of calculus. The gingivae were edematous with deep periodontal pockets and attachment loss, and the mandible contained localized alveolar bone necrosis. Panoramic radiography revealed severe alveolar bone loss. Serologic examination revealed that the level of IgG4 concentration was 199 mg/dL. Histopathological findings demonstrated significant lymphoplasmacytic infiltration. The immunohistochemical staining showed 50 scattered IgG4-positive plasma cells in a high-power field, and the IgG4/IgG cell ratio was >50%. The patient was finally diagnosed with IgG4-RD.Interventions:He then received multidisciplinary treatments: glucocorticoid treatment, nonsurgical periodontal treatment, sequestrectomy, and curettage. His gingival enlargement significantly improved without recurrence.Outcomes:His gingival enlargement significantly improved without recurrence.Lessons:Patients with generalized gingival enlargement and periodontitis who do not seem to respond to conventional periodontal therapy must be suspected of having periodontitis associated with systemic disease, such as IgG4-RD.