<s>[INST] <<SYS>> This is a medical question of type : causes <</SYS>> What causes Reticulohistiocytoma ? [/INST] What causes reticulohistiocytoma? While it is known that reticulohistiocytoma (RH) develop due to a rapid production of immune cells (histiocytes) in the skin or soft tissues, the cause of this process is not currently known. </s>