Name

ICD-O-1 Morphology

9720/3: Malignant histiocytosis
Effective 1978 - 1991

ICD-O-2 Morphology

9720/3: Malignant histiocytosis
Effective 1992 - 2000

ICD-O-3 Morphology

9751/3: Langerhans cell histiocytosis
Effective 2010 and later

Reportable

for cases diagnosed 1978 - 2000, 2010 and later

Primary Site(s)

See Module 7
Most common sites of involvement: bone, lung, soft tissue, lymph nodes, bone marrow

Abstractor Notes

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). All other forms of LCH are no longer malignant (/3 behavior) and are not reportable except for benign Brain and CNS tumors (9751/1).

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.

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.

Diagnostic Confirmation

This histology can be determined by positive histology (including peripheral blood) with or without genetics and/or immunophenotyping. Review the Definitive Diagnostic Methods, Immunophenotyping and Genetics Data sections below, and the instructions in the Hematopoietic Manual for further guidance on assigning Diagnostic confirmation.

Grade

Not Applicable

Module Rule

None

Alternate Names

Langerhans cell histiocytosis, disseminated

Definition

Langerhans cell histiocytosis (LCH) is a clonal neoplastic proliferation of Langerhans-type cells that express CD1a, langerin and S100 protein and show Birbeck granules by ultrastructural examination.

Definitive Diagnostic Methods

Genetic testing
Histologic confirmation
Immunophenotyping

Genetics Data

TR genes are clonally rearragned
X-linked androgen receptor gene assay (HUMARA)

Immunophenotyping

CD1a expression
CD30 absent
CD45 expression
CD68 positive
HLA-DR positive
Langerin (CD207) expression
S100 Protein expression
Vimentin positive

Treatments

Chemotherapy
Hormone therapy
Immunotherapy
Other therapy
Radiation therapy
Surgery

Transformations to

There are no known transformations

Transformations from

There are no known transformations

Corresponding ICD-9 Codes

202.5 Letterer-Siwe Disease

Corresponding ICD-10 Codes

C96.0 Letterer-Siwe Disease

Corresponding ICD-10-CM Codes (U.S. only)

C96.0 Multifocal and multisystemic (disseminated) Langerhans-cell histiocytosis (effective October 01, 2015)

Signs and Symptoms

Diarrhea
Dyspnea
Easy bruising or bleeding
Edema
Fever
Painful bone lesion
Polydipsia
Polyuria
Skin rash
Weight loss

Diagnostic Exams

Biopsy
Blood chemistry studies
Bone scan
BRAF testing
CT (CAT) scan
Endoscopy
Flow cytometry
Immunophenotyping
Liver function test
Neurological exam
PET (positron emission topography) scan
Physical exam and history
Ultrasound exam
Urinalysis
Water deprivation test

Progression and Transformation

Progression from initial focal disease multisystem involvement can occur, mostly in infants
Systemic and (rarely) multifocal disease can be complicated by hemophagocytic syndrome

Epidemiology and Mortality

Age: most cases occur in childhood
Incidence: 5 per million population per year
Race: more common in whites of northern Europena descent, rare in blacks
Survival: Unifocal disease (99% or greater), Multisystem disease (66% mortality)

Sources

Swerdlow SH, Campo E, Harris NL, Jaffe ES, Pileri SA, Stein H, Thiele J (Eds):
WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues (Revised 4th edition)
IARC: Lyon 2017
Section: Histiocytic and dendritic cell neoplasms
Pages: 470-472

International Classification of Diseases for Oncology, Third Edition, Second Revision. Geneva: World Health Organization, 2013.
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

National Cancer Institute
Section: General Information About Langerhans Cell Histiocytosis (LCH)
Pages: https://www.cancer.gov/types/langerhans/hp/langerhans-treatment-pdq#section/_178%20or%20http://www.cancer.gov/types/langerhans/patient/langerhans-treatment-pdq
Glossary