Search Database ICD-O-3 Code Lists

Name

Essential thrombocythemia (ET)

ICD-O-3 Morphology

9962/3: Essential thrombocythemia
Effective 2001 and later

Reportable

for cases diagnosed 2001 and later

Primary Site(s)

C421
Primary site must be bone marrow (C421). Blood and bone marrow are the primary sites of involvement.

Coding Manual: Hematopoietic Coding Manual (PDF)

Abstractor Notes

Essential thrombocythemia (ET) is part of the Myeloproliferative neoplasms (MPN) lineage table in the WHO 5th edition of Hematolymphoid Tumors. (See Appendix B in the Hematopoietic Manual, Table B2)

Thrombocytosis is the defining feature of this neoplasm in the absence of an obvious secondary cause, such as trauma, infection, reactive state, iron deficiency or injury.

A diagnosis of "post essential thrombocythemia myelofibrosis" is a progression of essential thrombocythemia and would be the same primary.

50-60% of patients will have a positive JAK2.
JAK2 status is collected in the following SSDI:
* NAACCR# 3862: JAK2

ET has three phases. These are all the same primary.
* Chronic: Most patients are diagnosed in this phase
* Accelerated
* Blast

No treatment is recommended for patients who are asymptomatic

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

Essential hemorrhagic thrombocythemia
Essential thrombocytosis
Idiopathic hemorrhagic thrombocythemia
Idiopathic thrombocythemia (thrombocytosis)
Primary thrombocythemia (thrombocytosis)

Definition

"Essential thrombocythemia (ET) is a myeloproliferative neoplasm (MPN) characterized by sustained thrombocytosis and increased numbers of large, mature megakaryocytes in a normocellular bone marrow." (WHO 5th edition).

Definitive Diagnostic Methods

Clinical diagnosis
Cytogenetics
Genetic testing
Histologic confirmation

Genetics Data

JAK2 at chromosome band 9p24.1
JAK2 V617F
MPL p.W515L/K-mutant thrombopoietin receptors phosphorylate wildtype JAK2

Immunophenotyping

None

Treatments

Chemotherapy
Immunotherapy
Other therapy

Transformations to

Transformations from

None

Same Primaries

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

D47.3 Essential (hemorrhagic) thrombocythemia

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

D47.3 Essential (hemorrhagic) thrombocythemia (effective October 01, 2015)

Signs and Symptoms

Bleeding from mucosal surfaces
Burning or tingling in the hands or feet
Erythromelalgia (redness and warmth of the hands or feet)
Fatigue
GI bleeding
Headache
Splenomegaly
Thrombocytosis
Thrombosis
Vision or hearing problems

Diagnostic Exams

Bone marrow aspiration and biopsy
CT (CAT) Scan
Cytogenetic analysis
Flow cytometry
Immunophenotyping
JAK 2 gene mutation test
Lumbar puncture
Molecular analysis
Peripheral blood smear
Physical exam and history

Progression and Transformation

None

Epidemiology and Mortality

Age: 50-60 years median age
Incidence: 1.55 per 100, 000 cases per year
Sex: no male or female predominance
Survival: 10-15 years median survival

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: Myeloproliferative neoplasms
Pages: Part A: 44-45

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® Adult Treatment Editorial Board. PDQ Myeloproliferative Neoplasms Treatment. Bethesda, MD: National Cancer Institute. Updated <09/27/24>. Available at: https://www.cancer.gov/types/myeloproliferative/hp/myeloproliferative-neoplasms-treatment. Accessed <01/22/25>. [PMID: 26389291]
Section: Myeloproliferative Neoplasms Treatment (PDQ®)-Health Professional Version
Pages: https://www.cancer.gov/types/myeloproliferative/hp/myeloproliferative-neoplasms-treatment
Glossary