Search Database ICD-O-3 Code Lists

Name

Erdheim-Chester disease (ECD)

ICD-O-3 Morphology

9749/3: Erdheim Chester Disease
Effective 2021 and later

Reportable

for cases diagnosed 2021 and later

Primary Site(s)

See Module 7
Erdheim Chester disease can occur in almost any organ, although the lymph nodes, spleen, and liver are generally spared.

Most common primary sites for Rosai Dorfman disease: lymph nodes, head and neck, skin, and CNS

See also abstractor notes

Coding Manual: Hematopoietic Coding Manual (PDF)

Abstractor Notes

This is a new reportable neoplasm for 2021. If the diagnosis is prior to 1/1/2021, it is not reportable.

Erdheim-Chester disease (ECD) is part of the Histiocyte/macrophage neoplasms lineage table in the WHO 5th edition of Hematolymphoid Tumors. (See Appendix B in the Hematopoietic Manual, Table B12)

Any organ or tissue can be infiltrated by Erdheim-Chester Disease.

Characteristic features on imaging studies are bilateral and symmetrical osteosclerosis of the diaphyseal and metaphyseal parts of the long bones. Osteolytic lesions may also be seen. PET/CT has a high specificity for the diagnosis of bone involvement by ECD.

Erdheim-Chester disease can be mistaken for Langerhans cell histiocytosis. Pathologic confirmation of the disease will need to be done to determine between Langerhans cell histiocytosis and Erdheim-Chester disease.

RDD most frequently involves lymph nodes, particularly in the cervical region. Extranodal disease occurs in 43% of cases, most often involving the head and neck, skin, and CNS.

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.

Module Rule

None

Alternate Names

Rosai-Dorfman disease
Rosai-Dorfman-Destombes disease
Sinus histiocytosis with massive lymphadenopathy

Definition

Erdheim–Chester disease (ECD) is a neoplasm characterized by an accumulation of mature histiocytes in many different organs and associated with inflammation and fibrosis. (WHO 5th edition)

Rosai–Dorfman disease (RDD) is a histiocytosis characterized by nodal or extranodal accumulation of large, S100-positive histiocytes/macrophages that commonly exhibit emperipolesis. (WHO 5th edition)

Definitive Diagnostic Methods

Cytogenetics
Genetic testing
Histologic confirmation
Immunohistochemistry
Immunophenotyping

Genetics Data

MAPK/ERK pathway gene mutations, including KRAS, NRAS, MAP2K1, ARAF, CSF1R, and (rarely) BRAF p.V600E

Immunophenotyping

CD1a- (no expression/negative)
CD4+ (expression/positive)
CD14+ (expression/positive)
CD68+ (expression/positive)
CD163+ (expression/positive)
CD207- (no expression/negative)
S100- (no expression/negative)

Treatments

Chemotherapy
Immunotherapy

Transformations to

There are no known transformations

Transformations from

There are no known transformations

Same Primaries

Corresponding ICD-10 Codes (Cause of Death codes only)

C96.2 Malignant mast cell tumor

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

C96.29 Other malignant mast cell neoplasm (effective October 01, 2015)

Signs and Symptoms

None

Diagnostic Exams

Biopsy
Bone marrow or aspiration and biopsy
Bone scan
BRAF testing
CT (CAT) scan
Immunophenotyping
PET (positron emission tomography) scan

Progression and Transformation

None

Epidemiology and Mortality

Age: 55-60 median age, pediatric cases rare
Incidence: less 1000 cases reported, male predominance
Survival: 32 months average

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: 245-251

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

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-pdq#section/_178%20or%20http://www.cancer.gov/types/langerhans/patient/langerhans-treatment-pdq
Glossary