Search Database ICD-O-3 Code Lists

Name

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL)

ICD-O-3 Morphology

9823/3: Chronic lymphocytic leukemia/SLL
Effective 2001 and later

Reportable

for cases diagnosed 1978 and later

Primary Site(s)

See Module 3: Rules PH5, PH6 and Module 7 (for primary site when peripheral blood and bone marrow not involved)
Common sites are the peripheral blood, bone marrow, lymph nodes, and tonsils. Less common extranodal sites such as the skin, CNS, kidney, and pleura, in rare cases, CLL/SLL may be detected in the parotid gland, lacrimal glands, tongue, ocular structures, prostate, lung, pericardium, or intestinal mucosa

Common metastatic sites: Bones, CNS, Liver
Spleen involvement is common due to dissemination of disease

See abstractor notes

Coding Manual: Hematopoietic Coding Manual (PDF)

Abstractor Notes

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is part of the Mature B-cell neoplasms lineage table in the WHO 5th edition of Hematolymphoid Tumors. (See Appendix B in the Hematopoietic Manual, Table B15)

CLL/SLL involves the peripheral blood, bone marrow, and lymphoid tissues such as lymph nodes, spleen, and tonsils. Less frequently, extranodal sites such as the liver, skin, CNS, kidney, pleura, and bones may be involved. In rare cases, CLL/SLL may be detected in the parotid gland, lacrimal glands, tongue, ocular structures, prostate, lung, pericardium, or intestinal mucosa, and it may accompany other pathologies at these sites.

CLL/SLL is frequently diagnosed via peripheral blood smear.

Watchful waiting, or observation, is a common treatment modality 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

Module 3: PH5, PH6

Alternate Names

Chronic lymphatic leukemia [OBS]
Chronic lymphocytic leukemia, B-cell type (includes all variants)
Chronic lymphoid leukemia [OBS]
Malignant lymphoma, lymphocytic, diffuse, NOS (see 9670/3 prior to 2010)
Malignant lymphoma, lymphocytic, NOS [OBS] (see 9670/3 prior to 2010)
Malignant lymphoma, lymphocytic, well differentiated, diffuse [OBS] (see 9670/3 prior to 2010)
Malignant lymphoma, small B lymphocytic, NOS (see 9670/3 prior to 2010)
Malignant lymphoma, small cell diffuse [OBS] (see 9670/3 prior to 2010)
Malignant lymphoma, small cell, NOS [OBS] (see 9670/3 prior to 2010)
Malignant lymphoma, small lymphocytic, diffuse, NOS [OBS] (see 9670/3 prior to 2010)
Malignant lymphoma, small lymphocytic, NOS [OBS] (see 9670/3 prior to 2010)
Small lymphocytic lymphoma (SLL) (see 9670/3 prior to 2010)

Definition

Chronic lymphocytic leukemia / small lymphocytic lymphoma (CLL/SLL) is a B-cell lymphoma comprising monomorphic small mature B cells that frequently coexpress CD5 and CD23. A peripheral blood diagnosis of chronic lymphocytic leukemia (CLL) requires a B-cell count of ≥ 5 × 109/L, with the characteristic morphology and immunophenotype. A tissue-based diagnosis of small lymphocytic lymphoma (SLL) requires organ enlargement (e.g. lymphadenopathy > 15 mm) and its infiltration by the above neoplastic B cells. Although CLL and SLL represent the same disease, the latter term is used for cases with < 5 × 109/L circulating B cells and nodal, splenic, or other extramedullary involvement. (WHO 5th edition)

Definitive Diagnostic Methods

Cytogenetics
Genetic testing
Histologic confirmation
Immunohistochemistry
Immunophenotyping

Genetics Data

ATM mutated genes (del[11q])
del(6q)
del(13q)-removes the DLEU2-miR-15-16 cluster
NOTCHI mutated genes
SF3B1 mutated genes
TP53 mutated genes (del[17q])
trisomy 12-more often seen in SLL presentation

Immunophenotyping

BCL6- (no expression/negative)
CD5+ (expression/positive)
CD10- - (no expression/negative)
CD19+ (PAX 5) (expression/positive)
CD20+ (expression/positive)
CD23+ (expression/positive)
CD34- (no expression/negative)
CD45+ (expression/positive)
CD79A+ (expression/positive)
CD138+ (no expression/negative)
TdT-(no expression/negative)
ZAP 70 (intracellular)+ (expression/positive)

Treatments

Chemotherapy
Immunotherapy
Other therapy

Transformations to

Transformations from

None

Same Primaries

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

C91.1 Chronic lymphocytic leukemia (CLL)

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

C91.1 Chronic lymphocytic leukemia of B-cell type (CLL) (effective October 01, 2015 - September 30, 2024)
C91.10 Chronic lymphocytic leukemia of B-cell type (CLL) not having achieved remission (effective October 01, 2024)
C91.11 Chronic lymphocytic leukemia of B-cell type (CLL), in remission (effective October 01, 2024)
C91.12 Chronic lymphocytic leukemia of B-cell type (CLL), in relapse (effective October 01, 2024)

Signs and Symptoms

Autoimmune hemolytic anemia
Extranodal infiltrates
Fatigue
Hepatomegaly
Infections
Lymphadenopathy
Splenomegaly

Diagnostic Exams

Blood chemistry studies
Bone marrow aspiration and biopsy
CT (CAT) scan
Cytogenetic analysis
Flow cytometry
Immunohistochemistry
Immunophenotyping
Laparoscopy (rarely performed)
Laparotomy (rarely performed)
Lymph node biopsy
PET (positron emission tomography) scan

Progression and Transformation

2-8% of CLL patients transform to DLBCL
<1% of CLL patients develop classical Hodgkin lymphoma

Epidemiology and Mortality

Age: 65 years median age (diagnosis in younger adults increasing)
Incidence: 2-6 cases per 100,000 per person per year (most common leukemia in adults in Western countries)
Race: slight female predominance
Survival: 293 month 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: Preneoplastic and neoplastic small lymphocytic proliferations
Pages: Part B: 368-377

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 Indolent B-Cell Non-Hodgkin Lymphoma Treatment. Bethesda, MD: National Cancer Institute. Updated <02/18/2025>. Available at: https://www.cancer.gov/types/lymphoma/hp/indolent-b-cell-lymphoma-treatment-pdq. Accessed <03/04/2025>. [PMID: 37437080]
Section: Indolent B-Cell Non-Hodgkin Lymphoma Treatment (PDQ®)–Health Professional Version
Pages: https://www.cancer.gov/types/lymphoma/hp/adult-nhl-treatment-pdq
Glossary