Rare diagnosis of IgG4-related systemic disease by lip biopsy in an international Sjögren syndrome registry.

IgG4-related disease has been recently defined as a distinct clinic-pathologic entity, characterized by dense IgG-4 plasmacytic infiltration of diverse organs, fibrosis, and tumefactive lesions. Salivary and lacrimal glands are a target of this disease and, when affected, may clinically resemble Küttner tumor, Mikulicz disease, or orbital inflammatory pseudotumor. In some patients, the disease is systemic, with metachronous involvement of multiple organs, including the pancreas, aorta, kidneys, and biliary tract. We report a 66-year-old man who presented with salivary gland enlargement and severe salivary hypofunction and was diagnosed with IgG4-related disease on the basis of a labial salivary gland biopsy. Additional features of his illness included a marked peripheral eosinophilia, obstructive pulmonary disease, and lymphoplasmacytic aortitis. He was evaluated in the context of a research registry for Sjögren syndrome and was the only 1 of 2594 registrants with minor salivary gland histopathologic findings supportive of this diagnosis