@article {Bruce-Brand697, author = {Cassandra Bruce-Brand and Johann W Schneider and Pawel Schubert}, title = {Rosai-Dorfman disease: an overview}, volume = {73}, number = {11}, pages = {697--705}, year = {2020}, doi = {10.1136/jclinpath-2020-206733}, publisher = {BMJ Publishing Group}, abstract = {Context Rosai-Dorfman disease is an uncommon histiocytic disorder most frequently presenting as bilateral cervical lymphadenopathy in children and young adults. Extranodal disease occurs in a significant proportion of patients. It has been recently classified as part of the {\textquoteleft}R group{\textquoteright} of histiocytoses by the Histiocyte Society in 2016. Cutaneous Rosai-Dorfman disease is regarded as a separate disease entity that falls into the {\textquoteleft}C group{\textquoteright} of histiocytoses according to this classification system. The pathogenesis was previously poorly understood; however, recent evidence demonstrating clonality in a subset of cases raises the possibility of a neoplastic process. A possible association with IgG4-related disease remains controversial.Objectives To provide a comprehensive review of Rosai-Dorfman disease, including nodal, extranodal and cutaneous forms, with a particular emphasis on new insights into the possible clonal nature of the disease; to discuss the recently revised classification of the histiocytoses by the Histiocyte Society; and to summarise the findings from the literature regarding the controversial association with IgG4-related disease.Data sources This review is based on published peer-reviewed English literature.Conclusions Classic Rosai-Dorfman disease, which may be sporadic or familial, is considered a separate entity from cutaneous disease, which is reflected in the revised classification of histiocytoses. An increase in IgG4-positive plasma cells may be seen in Rosai-Dorfman disease. This finding in isolation is of limited significance and should be interpreted with caution. Studies investigating the molecular profile of the disease show that in at least a subset of cases the disease is a clonal process. The classification of Rosai-Dorfman disease is therefore likely to change as our understanding of the aetiopathogenesis evolves.}, issn = {0021-9746}, URL = {https://jcp.bmj.com/content/73/11/697}, eprint = {https://jcp.bmj.com/content/73/11/697.full.pdf}, journal = {Journal of Clinical Pathology} }