Primary adult-onset macrophage activation syndrome with multisystemic tissue phagocytosis.

The histiocyte disorders are divided into the following 3 categories according to the specific lineage of the histiocytes involved and their biological behavior: the dendritic cell-related disorders, which include Langerhans cell histiocytosis and dermal dendrocyte disorders; the macrophage cell disorders, hemophagocytic lymphohistiocytosis being the main entity; and the malignant histiocyte disorders. We present a case of a 36-year-old woman who was referred to our hospital because of fever of unknown origin, lethargy, anemia, and impaired hepatic function. Following a thorough investigation, we diagnosed extensive histiocyte-mediated phagocytosis in many areas (skin, liver, bone marrow), without any identifiable cause.