To provide an overview of the CT and MRI imaging features of histiocytic disorders in adults. To perform a proper differential diagnosis in order to establish an optimal therapeutic approach in cases of these uncommon and poor prognosis diseases. To analyze the role of the radiologist in the diagnosis and evaluation of histiocytic disorders.

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...

1. Langerhans cell Histiocytosis LCH can affect most organ systems and imaging features are often not pathognomonic. Definitive diagnosis usually requires clinical features, histopathology and immunohistochemistry in addition to radiologic findings. A review of typical radiologic findings in LCH is shown in Fig. 3 (4). - Skeleton: The skeleton involvement is the most common radiographic manifestation and flat bones are the most common location for single-lesion, especially in adults. The skull is the most common flat bone involved. Lesion appears as well-defined “punched out” lytic...

Histiocytic disorders can rarely affect adults and present nonspecific image findings. The role of the radiologists in the diagnosis is relatively limited but, familiarity with typical radiographic features is essential for its identification and may promote accurate and timely diagnosis.

A. Santos Ángel; Madrid/ES - Author at Hospital Universitario Infanta Sofia I. Salmeron Beliz; San Sebastian De Los Reyes/ES - Author at Hospital Universitario Infanta Sofia J. Morán Marsili; Madrid/ES - Author at Hospital Universitario Infanta Sofia A. Aguado Toquero; Madrid/ES - Author at Hospital Universitario Infanta Sofia M. Pire Solaun; Madrid/ES - Author at Hospital Universitario Infanta Sofia A. Martin Diaz; Madrid/ES - Author at Hospital Universitario Infanta Sofia E. Dominguez-Franjo; Madrid/ES - Author at Hospital Universitario Infanta Sofia M. Ruiz Moreno; Madrid/ES -...

1.Jaffe R, Weiss LM, Facchetti F. Tumors derived from Langerhans cells. In: Swerdlow SH, Campo E, Harris NL, et al, eds. Work Health Organization classification of tumors of hematopoietic and lymphoid tissues. Lyonm France: IARC, 2008; 358. 2.Zaveri J, La Q, Yarmish G, et al. More than just Langerhans cell histiocytosis: a radiologic review of histiocytic disorders. Radiographics. 2014 Nov-Dec;34(7):2008-24. 3.La Barge DV, Salzman KL, Hansberger HR et al. Sinus histiocytosis with massive lymphadenopathy (Rosai-Dorfman disease): imaging manifestations in the head and neck. American Journal...