Rosai Dorfman Disease With Extensive Bony Involvement- A Diagnostic Dilemma.

Previously classified as Non Langerhan cell histiocytosis by the Working Group of Histiocytic Society in 1987 Rosai Dorfman Destombes disease was first described by Destombes in 1965 and later in 1969 by Rosai and Dorfman as a rare histiocytic disorder with sinus histiocytosis and massive lymphadenopathy. They exist in both nodal and extranodal forms. Immunohistochemistry is an essential part of diagnosis to differentiate between Langerhans cell histiocytosis and another malignant histiocytosis.