Rosai-Dorfman Disease of Right Atrium Mimicking Myxoma.

Rosai-Dorfman disease, or sinus histiocytosis with massive lymphadenopathy, is a rare multisystemic disorder that was first reported by Rosai and Dorfman in 1969. It is a distinct histioproliferative disorder due to overproduction of histiocytes, which accumulate in lymph nodes. The cardiac involvement of this disease is extremely rare, and until now, only 18 cases have been reported. We report the case of a 53-year-old woman with right atrial mass mimicking myxoma, which the histopathologic evaluation revealed to be Rosai-Dorfman disease of the right atrium.