T-lymphoblastic leukemia/lymphoma

ICD-O-1 Morphology

9821/3: Acute lymphoid leukemia

ICD-O-2 Morphology

9821/3: Acute lymphoid leukemia

ICD-O-3 Morphology

9837/3: Adult T-cell leukemia/lymphoma
Effective 2001 and later


for cases diagnosed 2001 and later

Primary Site(s)

See Module 4: Rules PH7, PH8
Most common sites of involvement: lymph nodes, peripheral blood

Abstractor Notes

Most ALL patients present with widespread lymph node involvement as well as peripheral blood involvement. The number of circulating neoplastic cells does not correlate with the degree of bone marrow involvement, suggesting that circulating cells are recruited from other organs such as the skin. In fact, the skin is the most common extra-lymphatic site of involvement.

The disease is usually systemic, involving the spleen and extranodal sites including skin, lung, liver, GI tract and CNS.

Several clinical variants have been identified:
1. Acute
2. Chronic
3. Lymphomatous
4. Smoldering ATLL

Patients often present with a high leukocyte count and often a large mediastinal mass or other tissue mass.

T-ALL comprises approximately 25% of adult ALL.

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.


Not Applicable

Module Rule

Module 4: PH7, PH8

Alternate Names

Cortical T ALL
Early T-cell precursor lymphoblastic leukemia
Lymphomatous T-cell leukemia/lymphoma
Mature T ALL
Precursor T-lymphoblastic leukemia/lymphoma


T-lymphoblastic leukemia/lymphoma (T-ALL) is a neoplasm of lymphoblasts committed to the T-cell lineage, typically composed of small to medium-sized blast cells with scant cytoplasm, moderately condensed to dispersed chromatin, and inconspicuous nucleoli, involving bone marrow and blood (T-ALL) or presenting with primary involvement of the thymus or of nodal or extranodal sites (T-LBL).

Definitive Diagnostic Methods

Bone marrow biopsy
Genetic testing
Histologic confirmation
Peripheral blood smear

Genetics Data

Alpha and Beta TCR loci at 14q11.2
Clonal rearrangement of T-cell receptor genes (TCR)
Gamma locus at 7p14-15
LCK at 1p34.3-35
LMO1 (also called RBTN1) at 11p15
LMO2 (also called RBTN2) at 11p13
MLLT1 (also called MLL) at 19p13
MYC at 8q24.1
PICALM-MLLT10 (also called CALM-AF10)
TAL1 locus fused to STIL (also called SIL)
TCF3 (also called E47)
TCF12 (also called HEB)


CCR4 positive
CD1a variably expressed
CD2 variably expressed
CD3 positive
CD4 variably expressed
CD5 variably expressed
CD7 positive
CD8 variably expressed
C13 expressed
CD19 positive
CD25 strongly expressed
CD33 expressed
CD79a positive
FLT3 mutation
KIT (CD117) positive


Hematologic Transplant and/or Endocrine Procedures
Hormone therapy
Radiation therapy

Transformations to

There are no known transformations

Transformations from

There are no known transformations

Corresponding ICD-9 Codes

200.1 Lymphosarcoma (Lymphoma presentation)
204.0 Acute lymphoid leukemia (Leukemia presentation)

Corresponding ICD-10 Codes

C83.5 Non-Hodgkin lymphoma lymphoblastic (diffuse) (Lymphoma presentation)
C91.0 Acute lymphoblastic leukemia (Leukemia presentation)

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

C83.5 Lymphoblastic (diffuse) lymphoma (Lymphoma presentation) (effective October 01, 2015)
C91.0 Acute lymphoblastic leukemia [ALL] (Leukemia presentation) (effective October 01, 2015)

Signs and Symptoms

High leukocyte count
Pleural effusions
Rapid growth mediastinal mass (anterior mediastinum)
Respiratory failure (emergency)

Diagnostic Exams

Blood chemistry studies
CT (CAT) scan
Cytogenetic analysis
Flow cytometry
Laparoscopy (rarely performed)
Laparotomy (rarely performed)
Lymph node biopsy
PET (positron emission tomography) scan

Progression and Transformation


Epidemiology and Mortality

Age: more common in adolescents than younger children and adults
Country: Patients from the Carribean basin than from Japan usually don't have peripheral blood involvement
Incidence: ~15% of childhood ALL
Sex: slight female predominance
Survival: higher risk disease than B-ALL


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: Precursor lymphoid neoplasms
Pages: 209-212

International Classification of Diseases for Oncology, Third Edition, Second Revision. Geneva: World Health Organization, 2020.
Section: ICD-O-3.2 (2020) Morphological Codes

National Cancer Institute
Section: General Information About Acute Lymphoid Leukemia