Rosai–Dorfman disease, also known as sinus histiocytosis with massive lymphadenopathy or sometimes as Destombes–Rosai–Dorfman disease, is a rare disorder of unknown cause that is characterized by abundant histiocytes in the lymph nodes or other locations throughout the body. Signs and symptoms The histiocytosis of Destombes–Rosai–Dorfman disease can occur in lymph nodes, causing lymphadenopathy, or can occur outside lymph nodes in extranodal disease. [Source: Wikipedia ]