Immunoglobulin G4-Related Disease: A Case Report.

Immunoglobulin G4-related disease (IgG4 RD) has a fair prognosis but its diagnosis has been difficult due to the condition's wide range of clinical manifestations, limited awareness among common practitioners, and various differentials. Here, we present a case of an elderly male who presented with recurrent dental caries, recurrent sinusitis, persistent dry mouth, and dry eyes along with bilateral parotid gland enlargement without any lymphadenopathy. The patient was evaluated further and found to have elevated levels of IgG4 and on histopathological examination of the parotid gland showed lymphocytic infiltrate with germinal centers without any granulomatous lesions and IgG4-positive plasma cells on immunohistochemistry (IHC). The patient was diagnosed with IgG4 RD and was started on corticosteroids, after which there was a symptomatic improvement.