Extranodal Rosai-Dorfman disease in children.

Sinus histiocytosis with massive lymphadenopathy (SHML), or Rosai-Dorfman disease (RDD), is a histiocytic disorder that usually presents with painless massive cervical lymphadenopathy. The course is usually self-limited, but treatment may be required in cases with compression of vital organs. Patients may present with extranodal involvement only, and in these cases the clinical and histologic diagnosis may be difficult. The authors describe three patients with RDD who had exclusive extranodal disease in the head and neck area, in whom the clinical presentation mimicked other more common conditions.