Autoimmune Diseases and Rosai-Dorfman Disease Coexist More Commonly than Expected: Two Case Reports.

BACKGROUND The educational objective of this study was to describe 2 case reports in which patients were found to have an autoimmune disease concomitantly with a rare, benign histiocytic disorder known as Rosai-Dorfman disease (RDD). It is unclear if there is an underlying association between autoimmune disease and RDD. Lymphadenopathy, although most frequently seen bilaterally in the cervical region in RDD, may be present anywhere. A biopsy with histologic confirmation is required to not only evaluate for malignancy in these cases, but also necessary to diagnose RDD. CASE REPORT We describe 2 cases in which RDD was found incidentally in 2 patients who concomitantly had known autoimmune diseases. The first patient's history included Factor II deficiency, antiphospholipid syndrome, and autoimmune hemolytic anemia; whereas the second patient had a positive antinuclear antibody test, elevated rheumatoid factor, positive lupus anticoagulant, and positive beta-2 glycoprotein 1 antibodies, as well as positive anticardiolipin antibody panel, immune mediated thrombocytopenia, and pernicious anemia. Lymphadenopathy and an enlarged mass were seen in these cases respectively, which were histologically proven to be RDD. Steroid therapy was the mainstay of treatment. CONCLUSIONS Autoimmune diseases are relatively common in the general population and it appears that RDD coexists more often than suspected. When lymphadenopathy or a mass is seen, especially in those with other autoimmune diseases, RDD should remain within the differential diagnosis. Further research is required to determine characteristics and optimal management of RDD. We have observed in the cases presented, that if the autoimmune disease is well controlled, RDD can be an indolent disease.