Below is an instruction from Human. Write a response.
    ### Instruction:
    What is (are) Reticulohistiocytoma ?
    ### Response:
    Reticulohistiocytoma (RH) is a rare benign lesion of the soft tissue. It belongs to a group of disorders called non-Langerhans cell histiocytosis and is a type of reticulohistiocytosis, all of which are types of histiocytosis. Histiocytosis is a condition in which there is rapid production (proliferation) of histiocytes (immune cells) in the skin or soft tissues.
    