[Rosai-Dorfman disease: a clinicopathologic analysis and whole exome sequencing in 23 cases]

Objective: To evaluate the clinicopathologic features of Rosai-Dorfman disease (RDD) , and elucidate the potential pathogenesis by whole exome sequencing (WES) . Methods: Clinico-pathological data of 23 RDD patients diagnosed between 2010 and 2018 in Changhai hospital were reviewed, and 9 paraffin-embedded specimens were performed for WES. Results: The median age of 23 RDD patients was 47 (10-79) years. Of them, 19 cases had extranodal lesions, 3 had nodal lesions, and 1 had nodal and extranodal lesions coincidently. All patients received surgery for lesion resection. Histiocytosis in lymph node sinuses or in extranodal tissues accompanied by lymphocyte phagocytosis are typical pathological features of RDD. Immunohistochemical staining shows histocytes are positive for S100, CD68 and CDl63, and negative for CD1a. mTOR, KMT2D and NOTCH1 mutations were detected with WES in these cases. Conclusion: Mutations in mTOR, KMT2D and NOTCH1 genes may be involved in the pathogenesis of RDD, and their clinical significance needs to be further studied.