Sinus histiocytosis with massive lymphadenopathy: evidence for its relationship to macrophages and for a cytokine-related disorder

Aims: Sinus histiocytosis with massive lymphadenopathy (SHML) or Rosai-Dorf man disease is a rare histiocytic disorder of unknown origin. Immunophenoty pically the histiocytes of SHML express intensively the S100 protein and in addition a panel of macrophage-associated antigens. Their exact relationsh ip to either monocytes/macrophages or immune accessory dendritic cells is, however, still controversial. Methods and results: In this report recurrent nodal and extranodal manifest ations of SHML of a 70-year-old patient were analysed by differential pheno typing using a panel of monoclonal and polyclonal antibodies to macrophage and immune accessory dendritic cell related antigens and by applying nonrad ioactive in-situ hybridization. Conclusions: We conclude that stimulation of monocytes/macrophages via macr ophage colony stimulating factor (M-CSF) leading to immune suppressive macr ophages represents a main mechanism for the pathogenesis of SHML. The study further provides evidence for the monocyte/macrophage but not dendritic ce ll differentiation of SHML histiocytes.