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This neoplasm is not reportable EXCEPT for Brain and CNS Sites.
Name
ICD-O-3 Morphology
9751/1: Langerhans cell histiocytosis
Effective
2021 and later
Reportability
This neoplasm is not reportable EXCEPT for Brain and CNS Sites
Primary Site(s)
See Module 7
This hematopoietic disease is not reportable for the U.S. except for primary sites C700-C729, C751-C753.
Canada, refer to your specific province for reportability requirements.
Most common sites of involvement: bone, lung, soft tissue, lymph nodes, bone marrow
The most commonly involved bones include the craniofacial bones, femur, spine, pelvis, and/or ribs.
See abstractor notes
Canada, refer to your specific province for reportability requirements.
Most common sites of involvement: bone, lung, soft tissue, lymph nodes, bone marrow
The most commonly involved bones include the craniofacial bones, femur, spine, pelvis, and/or ribs.
See abstractor notes
Abstractor Notes
Langerhans cell histiocytosis (LCH) (NOS) is part of the Langerhans cell and other dendritic cell neoplasms lineage table in the WHO 5th edition of Hematolymphoid Tumors. (See Appendix B in the Hematopoietic Manual, Table B11)
Reportability for Langerhans Cell Histiocytosis changed in 2021. For cases with diagnosis date before 2021, make sure you choose the "Help me code for diagnosis years" to 2020 or earlier.
Per the IARC/WHO Committee for ICD-O and included in the WHO Tumors of Hematopoietic and Lymphoid Tissues, Revised 4th Ed, Volume 2, only LCH disseminated/multisystem is now assigned /3 behavior (malignant).
LCH, disseminated/multisystem is a combined pathological/clinical diagnosis. Microscopic (histological) confirmation of LCH may be done, but may not document that the tumor is disseminated/ multisystem. The disseminated/multisystem diagnosis is based on clinical evaluation by the managing/treating physician and is based on multiple areas of involvement. Not all suspected sites of involvement need to be biopsied or surgically resected.
If the only information you have is a pathology report that has LCH, NOS with no clinical evaluation on the extent of involvement, do not abstract the case. Only reportable if benign Brain and CNS.
Langerhans cell histiocytosis presents in several different forms
1. DISSEMINATED/MULTISYSTEM: Occurs in infants who present with fever, cytopenia, skin and bone lesions, and hepatosplenomegaly. Pulmonary disease in childhood is clinically variable. The skin, bone, and marrow are preferential sites of involvement. The liver and spleen are also common sites; however, they are typically metastatic and not the primary site. Involvement of bone marrow, liver, and lung are regarded as high-risk factors. (9751/3)
2. SOLITARY/UNIFOCAL form: Usually occurs in older children or adults who most commonly present with a lytic bone lesion eroding the cortex. Solitary lesions may occur at other sites as mass lesions or enlarged lymph nodes. Other sites include adjacent soft tissue (skull, femur, vertebra, pelvic bones, and ribs) and less commonly lymph nodes, skin and lung. (Only reportable if benign Brain and CNS, See 9751/1)
3. MULTIFOCAL/UNISYSTEM multifocal disease-Usually occurs in young children who present with multiple or sequential destructive bone lesions often associated with adjacent soft tissue masses. Skull and mandibular involvement is common. Diabetes insipidus follows cranial involvement. (Only reportable if benign Brain and CNS, See 9751/1)
Self-healing Langerhans cell histiocytosis (LCH) of the skin means that the disease regressed without treatment. This is a known phenomenon and is non reportable.
Reportability for Langerhans Cell Histiocytosis changed in 2021. For cases with diagnosis date before 2021, make sure you choose the "Help me code for diagnosis years" to 2020 or earlier.
Per the IARC/WHO Committee for ICD-O and included in the WHO Tumors of Hematopoietic and Lymphoid Tissues, Revised 4th Ed, Volume 2, only LCH disseminated/multisystem is now assigned /3 behavior (malignant).
LCH, disseminated/multisystem is a combined pathological/clinical diagnosis. Microscopic (histological) confirmation of LCH may be done, but may not document that the tumor is disseminated/ multisystem. The disseminated/multisystem diagnosis is based on clinical evaluation by the managing/treating physician and is based on multiple areas of involvement. Not all suspected sites of involvement need to be biopsied or surgically resected.
If the only information you have is a pathology report that has LCH, NOS with no clinical evaluation on the extent of involvement, do not abstract the case. Only reportable if benign Brain and CNS.
Langerhans cell histiocytosis presents in several different forms
1. DISSEMINATED/MULTISYSTEM: Occurs in infants who present with fever, cytopenia, skin and bone lesions, and hepatosplenomegaly. Pulmonary disease in childhood is clinically variable. The skin, bone, and marrow are preferential sites of involvement. The liver and spleen are also common sites; however, they are typically metastatic and not the primary site. Involvement of bone marrow, liver, and lung are regarded as high-risk factors. (9751/3)
2. SOLITARY/UNIFOCAL form: Usually occurs in older children or adults who most commonly present with a lytic bone lesion eroding the cortex. Solitary lesions may occur at other sites as mass lesions or enlarged lymph nodes. Other sites include adjacent soft tissue (skull, femur, vertebra, pelvic bones, and ribs) and less commonly lymph nodes, skin and lung. (Only reportable if benign Brain and CNS, See 9751/1)
3. MULTIFOCAL/UNISYSTEM multifocal disease-Usually occurs in young children who present with multiple or sequential destructive bone lesions often associated with adjacent soft tissue masses. Skull and mandibular involvement is common. Diabetes insipidus follows cranial involvement. (Only reportable if benign Brain and CNS, See 9751/1)
Self-healing Langerhans cell histiocytosis (LCH) of the skin means that the disease regressed without treatment. This is a known phenomenon and is non reportable.
Alternate Names
Acute progressive histiocytosis X (see 9751/3 prior to 2021)
Eosinophilic granuloma (see 9751/3 prior to 2021)
Langerhans cell histiocytosis, generalized (see 9751/3 prior to 2021)
Hand-Schuller-Christian disease [OBS] (see 9751/3 prior to 2021)
Histiocytosis X, NOS [OBS] (see 9751/3 prior to 2021)
Langerhans cell histiocytosis, mono-stotic (unifocal) (see 9751/3 prior to 2021)
Letterer-Siwe disease [OBS] (see 9751/3 prior to 2021)
Nonlipid reticuloendotheliosis [OBS] (see 9751/3 prior to 2021)
Definition
Langerhans cell histiocytosis (LCH) is a clonal neoplasm of myeloid dendritic cells that have a Langerhans cell phenotype (CD1a and CD207 expression) and lack high-grade cytological features. (WHO 5th edition)
Single-system LCH (SS-LCH): Occurs in one organ or one system and can be unifocal or multifocal. Commonly there is skin, pituitary, or bone involvement
Single-system LCH (SS-LCH): Occurs in one organ or one system and can be unifocal or multifocal. Commonly there is skin, pituitary, or bone involvement
Genetics Data
This data item does not apply
Immunophenotyping
This data item does not apply
Corresponding ICD-10 Codes (Cause of Death codes only)
D76.0 Langerhans' cell histiocytosis, not elsewhere classified
Corresponding ICD-10-CM Codes (U.S. only)
C96.6 Unifocal Langerhans-cell histiocytosis (effective October 01, 2015)
Sources
WHO Classification of Tumours Editorial Board. Haematolymphoid tumours. Lyon (France): International Agency for Research on Cancer; 2024. (WHO classification of tumours series, 5th ed.; vol. 11). https://publications.iarc.who.int/637.
Section: Histiocytic/dendritic cell neoplasms
Pages: Part A: 230-233
Section: Histiocytic/dendritic cell neoplasms
Pages: Part A: 230-233
International Classification of Diseases for Oncology, 3rd edition (including revisions). Geneva: World Health Organization, 2001, 2011, 2020.
Section: ICD-O-3.2 (2020) Morphological Codes
Pages: http://www.iacr.com.fr/index.php?option=com_content&view=category&layout=blog&id=100&Itemid=577
Section: ICD-O-3.2 (2020) Morphological Codes
Pages: http://www.iacr.com.fr/index.php?option=com_content&view=category&layout=blog&id=100&Itemid=577
PDQ® Pediatric Treatment Editorial Board. PDQ Langerhans Cell Histiocytosis Treatment. Bethesda, MD: National Cancer Institute. Updated <01/06/2025>. Available at: https://www.cancer.gov/types/langerhans/hp/langerhans-treatment-pdq. Accessed <02/28/2025>. [PMID: 26389240]
Section: Langerhans Cell Histiocytosis Treatment (PDQ®)–Health Professional Version
Pages: https://www.cancer.gov/types/langerhans/hp/langerhans-treatment-
Section: Langerhans Cell Histiocytosis Treatment (PDQ®)–Health Professional Version
Pages: https://www.cancer.gov/types/langerhans/hp/langerhans-treatment-
