Rosai-Dorfman disease of multiple organs, including the epicardium: An unusual case with poor prognosis.

Rosai-Dorfman disease (RDD) is a benign proliferative histiocytic disorder predominantly of the lymph nodes with extranodal involvement in some cases. However, serous membranes are seldom involved in the extranodal cases, and epicardial involvement is never reported. Most RDD cases show a self-limiting process with good prognosis and corticosteroid treatment in some patients exhibiting good effect. We recently observed a case of RDD primarily manifesting pericardial and bilateral pleural effusion that finally led to death, and corticosteroid treatment showed little effect. Autopsy showed the characteristic S100-positive and CD68-positive histiocytes exhibiting emperipolesis in the lungs, pleura, epicardium, mediastinal lymph nodes, and colon. This case illustrates the importance of RDD in the differential diagnosis of effusion in multiple serous cavities. The failure of corticosteroid therapy in this patient and her death showed the poor prognosis of some patients with RDD. Moreover, to our knowledge, epicardial involvement of RDD has not been reported.