Langerhans cell histiocytosis

Histiocyte Society[1]Emile JF, Abla O, Fraitag S, et al. Revised classification of histiocytoses and neoplasms of the macrophage-dendritic cell lineages. Blood. 2016 Jun 2;127(22):2672-81. https://ashpublications.org/blood/article/127/22/2672/35156/Revised-classification-of-histiocytoses-and http://www.ncbi.nlm.nih.gov/pubmed/26966089?tool=bestpractice.com [4]Goyal G, Tazi A, Go RS, et al. International expert consensus recommendations for the diagnosis and treatment of Langerhans cell histiocytosis in adults. Blood. 2022 Apr 28;139(17):2601-21. https://ashpublications.org/blood/article/139/17/2601/484364/International-expert-consensus-recommendations-for http://www.ncbi.nlm.nih.gov/pubmed/35271698?tool=bestpractice.com [67]National Comprehensive Cancer Network. NCCN clinical practice guidelines in oncology: histiocytic neoplasms [internet publication]. https://www.nccn.org/guidelines/category_1

The diagnosis of LCH is based on clinical and radiological findings in combination with histopathological analyses identifying tissue infiltration by histiocytes with ultrastructural or immunophenotypic characteristics of Langerhans cells. Lesional cells demonstrate S100, CD1a, and langerin (CD207) positivity.

Euro Histio Network: risk stratification (paediatric LCH)[2]Haupt R, Minkov M, Astigarraga I, et al; Euro Histio Network. Langerhans cell histiocytosis (LCH): guidelines for diagnosis, clinical work-up, and treatment for patients till the age of 18 years. Pediatr Blood Cancer. 2013 Feb;60(2):175-84. https://onlinelibrary.wiley.com/doi/10.1002/pbc.24367 http://www.ncbi.nlm.nih.gov/pubmed/23109216?tool=bestpractice.com

Multi-system LCH

• Low risk: excellent prognosis and no risk organ (i.e., liver, spleen, bone marrow) involvement

• High risk: poor prognosis and involves at least one risk organ.