CD68 and sinus histiocytosis with massive lymphadenopathy: The specific histological features of RDD are positive S100 protein and CD68 immune markers, abnormal cell proliferation, and lymphocyte phagocytosis.[13–15] The typical pathological manifestation of RDD is that the lymph node contour in the node is still retained, the lymph follicles are atrophic, and the germinal center is not obvious.