Rosai-Dorfman Disease Presenting in the Parotid Gland With Features of IgG4-Related Sclerosing Disease

Rosai-Dorfman disease (RDD) is an infrequently encountered disorder characterized by histiocytes exhibiting emperipolesis and varying degrees of chronic inflammatory cell infiltrates. It is generally considered an important differential diagnosis of IgG4related sclerosing disease because of their similar histopathologic features. We report herein a case of RDD in the parotid gland with an increase in the absolute number of IgG4plasma cells as...