IgG4-rich reactive lymphoid hyperplasia of the lacrimal gland.

We describe an otherwise healthy 24-year-old woman with reactive lymphoid hyperplasia of one lacrimal gland. She was found to have modest elevation of serum IgG4 and high density of IgG4+ plasma cells in her lacrimal gland, ranging from 40% to 60% of IgG+ plasma cells. The patient transiently responded to systemic corticosteroids before treatment with rituximab. IgG4-rich reactive lymphoid hyperplasia of the lacrimal gland is neither an established part of IgG4-related disease spectrum nor a known precursor lesion to lymphoma. Although there is a plausible risk of transforming to IgG4-related disease or to lymphoma, the biological potential and natural history of IgG4-rich reactive lymphoid hyperplasia remains to be determined.