There are competing systems for classifying<unk> . According to the 1999 classification proposed by the World Health Organization, they can be divided into three categories. However, the classifications in ICD10 and MeSH are slightly different, as shown below: Name WHO ICD10 MeSH Langerhans cell<unk>  (LCH) I Langerhans-cell<unk>  Juvenile xanthogranuloma (JXG) II non-Langerhans-cell<unk>  Hemophagocytic lymphohistiocytosis (HLH) II non-Langerhans-cell<unk>  Niemann–Pick disease II non-Langerhans-cell<unk>  Sea-blue<unk>  II - non-Langerhans-cell<unk>  Acute monocytic leukemia III malignant histiocytic disorders Malignant<unk>  III malignant histiocytic disorders Erdheim–Chester disease II malignant histiocytic disorders Alternatively,<unk>  may be divided into the following groups: * X-type<unk>  * Non-X<unk>  Lymphohistiocytosis is a similar immune system disease characterized by the inappropriate activation of natural killer cells, CD8+ cytotoxic T-cells, and macrophages, involving principally the liver, spleen and central nervous system and associated with severe lymphoid atrophy.
Histiocytosis
Non-Hodgkin lymphoma
Angiolymphoid hyperplasia with eosinophilia
Reticulohistiocytoma
Progressive nodular histiocytosis
Intravascular lymphomas
B-cell lymphoma
Tuberculous lymphadenitis