Overview of Histiocytic and Dendritic Disorders by the 5th Version of WHO Classifi Cation of Hematolymphoid Tumours from 2022

Background: Histiocytoses are rare disorders characterized by the accumulation of macrophages, dendritic cells, or monocyte-derived cells in various tissues and organs of children and adults, with a wide range of clinical manifestations, presentations, and histology. The histiocytoses are classified according to the WHO Classification, the last version of which was published in 2022, or according to the Histiocyte Society Classification, with the last version published in 2016.

Purpose: This text provides an overview of histiocytoses as described in the WHO Classification 2022.