Clinicopathological Features and Expression of CD30, OCT2, and Cyclin D1 in Rosai-Dorfman Disease: A Retrospective Case Series.

Rosai-Dorfman disease (RDD) is a rare sinus histiocytosis characterized by massive lymphadenopathy. The purpose of this study was to retrospectively analyze the clinicopathological features of RDD and the immunohistochemical expression of CD30, OCT2, and cyclin D1. We also compared RDD with reactive sinus histiocytosis (RSH), Langerhans cell histiocytosis (LCH), inflammatory myofibroblastic tumor (IMT), and IgG4-related disease (IgG4-RD) to assess differences in their immunohistochemical profiles. Ten cases of RDD were included; all patients were male, with a median age of 37 years (range: 17 to 58 y). Three cases involved lymph nodes, while 7 were extranodal. The clinical manifestations were nonspecific and varied with the site involved. Pathologically, most RDD cases showed alternating light and dark histiocytic areas with varying degrees of inflammatory cell infiltration and the characteristic finding of emperipolesis. Immunohistochemistry showed positive rates for CD30, OCT2, and cyclin D1 in RDD of 100%, 90%, and 100%, respectively, which were significantly higher than those in RSH, LCH, IMT, and IgG4-RD. RDD has no specific clinical manifestations, and diagnosis relies primarily on histopathology and immunohistochemistry. CD30, OCT2, and cyclin D1 can serve as ancillary markers for the pathologic diagnosis and differential diagnosis of RDD.