Primary Rosai-Dorfman disease of bone: a clinicopathologic study of 15 cases.

Sinus histiocytosis with massive lymphadenopathy or Rosai-Dorfman disease (RDD) is a rare histiocytic proliferative disorder of unknown etiology. Most patients present with lymph node involvement manifesting as adenopathy; however, RDD may arise primarily in a variety of extranodal sites, including