Histiocytic disorders are a group of diseases derived from macrophages and dendritic cells. They include some rare multisystem diseases with a wide and heterogeneous clinical radiological spectrum. There have been several classifications for histiocytic disorders over time but the World Health Organization´s contemporary classification organizes them into three groups: dendritic cell disorders, macrophage-related disorders and malignant histiocytic disorders, according to the type of histiocyte involved (1). Some of the diseases included in these groups are shown in Fig. 1 .

Langerhans cell histiocytosis (LCH) is the most common dendritic cell disorder. The clinical manifestation of LCH ranges from self-limited to rapidly progressive course and fatal disease. Nearly any part of the body can be affected.

Erdheim-Chester disease (ECD) is more common in middle age and is a multisystemic disease with widespread manifestations with variable severity.

Juvenile Xanthogranuloma (JXG) mainly affects infants and small children, although it can also occur in adults of all ages. The most common manifestations are dermal and, less commonly, may involve other organ systems. (2).

Rosai-Dorfman disease (RDD) typical manifestation is painless massive lymphadenopathy, being cervical lymph nodes the most typical location. Extranodal disease is seen in up to 43% of RDD disease, leading to a wide range of imaging findings. SNC is the most common site of involvement (3).

Clinical manifestations of haemophagocytic lymphohistocytosis (HLH) are so nonspecific that the diagnosis is a challenge. There are some clinical and analytical criteria that can be useful in the differential diagnosis ( Fig. 2 ).