Chronic lymphocytic leukemia/small lymphocytic lymphoma

ICD-O-1 Morphology
9823/3: Chronic lymphocytic leukemia/SLL
Effective 1978 - 1991
ICD-O-2 Morphology
9823/3: Chronic lymphocytic leukemia/SLL
Effective 1992 - 2000
ICD-O-3 Morphology
9823/3: Chronic lymphocytic leukemia/SLL
Effective 2001 and later
for cases diagnosed 1978 and later
Primary Site(s)
See Module 3: Rules PH5, PH6
Most common sites of involvement: bone marrow, peripheral blood, lymph nodes

Not Applicable
Module Rule
Module 3: PH5, PH6
Alternate Names
CLL by definition involves blood and bone marrow at time of diagnosis with absolute increase in number of lymphocytes in blood morphologically and immunophenotypically consistent with diagnosis.

Neoplasm of monomorphic small round B lymphocytes admixed with prolymphocytes and paraimmunoblasts, in peripheral blood, marrow, nodes, usually expressing CD5, CD23.
Small lymphocytic lymphoma, chronic lymphocytic leukemia considered ends of continuous spectrum in which lymphadenopathy or peripheral blood involvement most prominent, respectively.
Abstractor Notes
Code 9823/3 is used for CLL, SLL, and CLL/SLL. CLL and SLL are no longer coded separately because it is almost impossible to differentiate between the two diseases. See the hematopoietic PH rules for information on coding primary site for CLL/SLL. CLL is the most common leukemia of adults in Western countries. The incidence of CLL is very low in Eastern countries and in immigrants from Eastern countries.

CLL is frequently diagnosed by flow cytometry (immunophenotyping), but can also be diagnosed via biopsy (bone marrow).

Flow cytometry is also used for ZAP 70, which is a predictor for aggressive vs indolent disease. If the ZAP 70 is positive, that means the disease is more aggressive and will need closer follow up. If the ZAP 70 is negative, then the disease is on a more indolent course. If the disease is more aggressive, treatment timing will change.

Treatments include donor lymphocyte infusion, which is a type of immunotherapy.

The treatment-free survival time was 30 months for ZAP-70 negative patients and 18 months for ZAP-70 positive patients.
Definitive Diagnostic Methods
Flow cytometry
Genetic testing
Histologic confirmation
Genetics Data
IG gene rearrangement
Ig heavy and light chain genes rearranged; abnormal karyotypes in 80%:trisomy 2: 20%, del at 13q14 in 50%, del at 11q22-23 in 20%, del at 6q21 in 5%, del at 17p13 in 10%
Weak or dim surface IgM/IgD
Hormone therapy
Transformations from
Corresponding ICD-9 Codes
204.1 Chronic lymphoid leukemia
Corresponding ICD-10 Codes
C91.1 Chronic lymphocytic leukemia
Corresponding ICD-10-CM Codes (U.S. only)
C91.1 Chronic lymphocytic leukemia of B-cell type (CLL) (effective October 01, 2015)
C83.0 Small cell B-cell lymphoma (SLL) (effective October 01, 2015)
Diagnostic Exams
CT (CAT) scan
Complete blood count (CBC)
Laparoscopy (rarely performed)
Laparotomy (rarely performed)
MRI (magnetic resonance imaging)
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