AJHE2311 - CME/CMLE - How I diagnose Rosai-Dorfman Disease-How I diagnose Rosai-Dorfman Disease

How I diagnose Rosai-Dorfman Disease

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The document discusses Rosai-Dorfman disease (RDD), a histiocytic disorder that involves both nodal and extranodal sites. RDD was historically considered benign but is now classified as a histiocytic neoplasm due to the presence of MAPK/ERK pathway mutations in many cases. The diagnosis of RDD involves a panel of immunostains and morphological characterization of histiocytes. RDD can manifest in various organs, with management tailored to individual patients based on the extent of organ involvement and clinical symptoms. Targeted therapy with MEK inhibitors like cobimetinib is recommended for patients with RDD harboring MAPK/ERK pathway mutations. The document also highlights the challenges in differentiating RDD from other histiocytic disorders like Langerhans cell histiocytosis and Erdheim-Chester disease and includes illustrative case presentations. Diagnosis confirmation involves a multidisciplinary approach and using immunohistochemistry panels.<br /><br />The document emphasizes the importance of integrating clinical, radiological, histological, and genetic features to diagnose RDD accurately. Various molecular genetic features, including MAPK/ERK pathway mutations, are discussed. The differential diagnosis of RDD includes reactive fibrohistiocytic proliferations, IgG4-related disease, lymphomas, and other histiocytic neoplasms. The article provides informative case studies illustrating the diagnosis and management of RDD, demonstrating the utility of immunohistochemistry and molecular testing in confirming RDD and guiding targeted therapy decisions.

Keywords

Rosai-Dorfman disease

RDD

histiocytic disorder

MAPK/ERK pathway mutations

immunostains

histiocytes

MEK inhibitors

Langerhans cell histiocytosis

Erdheim-Chester disease

multidisciplinary approach