Primary Rosai-Dorfman Disease of Bone: A Report of Two Cases.

Rosai-Dorfman disease (RDD), sometimes known as sinus histiocytosis with massive lymphadenopathy, is a rare histiocytic disorder that most commonly presents as painless, massive cervical lymphadenopathy in young adults. Extranodal disease can occur in up to 40% of patients but primary involvement of bone is rare. We present two cases of primary RDD of bone: one case of multifocal osseous RDD presenting as a painful lesion in the elbow, and one case of a solitary osseous lesion presenting as a painful lesion in the wrist.