The disease spectrum results from clonal accumulation and proliferation of cells resembling the epidermal dendritic cells called Langerhans cells, sometimes called Dendritic Cell Histiocytosis. These cells in combination with lymphocytes, eosinophils, and normal histiocytes form typical LCH lesions that can be found in almost any organ.[2] A similar set of diseases has been described in canine histiocytic diseases.