Histiocytosis: a review focusing on neuroimaging findings Histiocitoses: uma revisão focada em achados de neuroimagem

Objective: Histiocytosis is a systemic disease that usually affects the central nervous system. The aim of this study is to discuss the neuroimaging characteristics of Langerhans cell histiocytosis (LCH), the most common of these diseases; and the non-Langerhans cells histiocytosis (NLCH), which includes entities such as hemophagocytic syndrome, Erdheim-Chester and Rosai-Dorfman diseases. Method: Literature review and illustrative cases with pathologic confirmation. Results: In LCH, the most common findings are 1) osseous lesions in the craniofacial bones and/or skull base; 2) intracranial, extra-axial changes; 3) intra-axial parenchymal changes (white and gray matter); 4) atrophy. Among the NLCH, diagnosis usually requires correlation with clinical and laboratory criteria. The spectrum of presentation includes intraparenchymal involvement, meningeal lesions, orbits and paranasal sinus involvement. Conclusion: It is important the recognition of the most common imaging patterns, in order to include LCH and NLCH in the differential diagnosis, whenever pertinent.