T-prolymphocytic leukaemia


Haematolymphoid Tumours (5th ed.)

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Primary Author(s)*

Parastou Tizro, MD

WHO Classification of Disease

(Will be autogenerated; Book will include name of specific book and have a link to the online WHO site)

Structure Disease
Book
Category
Family
Type
Subtype(s)

Definition / Description of Disease

T-prolymphocytic leukemia (T-PLL) is an aggressive form of T-cell leukemia marked by the proliferation of small to medium-sized prolymphocytes exhibiting a mature post-thymic T-cell phenotype. This condition is characterized by the juxtaposition of TCL1A or MTCP1 genes to a TR locus, typically the TRA/TRD locus.

Synonyms / Terminology

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Epidemiology / Prevalence

T-PLL is a rare disorder, comprising about 2% of all mature lymphoid leukemia cases in adults. It primarily occurs in the elderly, with a median age of 65 years (ranging from 30 to 94 years), and shows a slight male predominance with a male to female ratio of 1.33:1.

Clinical Features

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Signs and Symptoms Hepatosplenomegaly (Frequently observed)

Generalized lymphadenopathy with slightly enlarged lymph nodes (Frequently observed

Cutaneous involvement (20%)

Malignant effusions (15%)

Asymptomatic and indolent phase (30% of cases)

Laboratory Findings Anaemia and thrombocytopenia

Marked lymphocytosis > 100 × 10^9/L (75% of cases)

Sites of Involvement

Peripheral blood, bone marrow, spleen, liver, lymph node, and sometimes skin and serosa

Morphologic Features

Blood smears display anemia, thrombocytopenia, and leukocytosis, predominantly of atypical lymphocytes. Bone marrow aspirates show aggregates of neoplastic lymphoid cells.

Immunophenotype

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Finding Marker
Positive (universal) CD2, CD3 (may be weak), CD5, CD7
Positive (subset) CD4 (in some cases CD4+/CD8+ or CD4-/CD8+), CD52
Negative (universal) TdT, CD1a
Negative (subset) CD8 (in some cases CD4+/CD8+ or CD4-/CD8+)

Chromosomal Rearrangements (Gene Fusions)

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Chromosomal Rearrangement Genes in Fusion (5’ or 3’ Segments) Pathogenic Derivative Prevalence Diagnostic Significance (Yes, No or Unknown) Prognostic Significance (Yes, No or Unknown) Therapeutic Significance (Yes, No or Unknown) Notes
inv(14)(q11q32)

t(14;14)(q11;q32)

TCL1A/TRD EXAMPLE: der(22) EXAMPLE: 20% (COSMIC)

EXAMPLE: 30% (add reference)

Yes EXAMPLE: No Yes EXAMPLE:

The t(9;22) is diagnostic of CML in the appropriate morphology and clinical context (add reference). This fusion is responsive to targeted therapy such as Imatinib (Gleevec) (add reference).

t(X;14)(q28;q11.2) MTCP1/TRD Low (5%) Yes

Individual Region Genomic Gain / Loss / LOH

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Chr # Gain / Loss / Amp / LOH Minimal Region Genomic Coordinates [Genome Build] Minimal Region Cytoband Diagnostic Significance (Yes, No or Unknown) Prognostic Significance (Yes, No or Unknown) Therapeutic Significance (Yes, No or Unknown) Notes
8 Gain idic(8)(p11.2)

t(8;8)(p11.2;q12)

trisomy 8q

chr8 No No No EXAMPLE:

Common recurrent secondary finding (70-80% of cases).[1]

Characteristic Chromosomal Patterns

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Chromosomal Pattern Diagnostic Significance (Yes, No or Unknown) Prognostic Significance (Yes, No or Unknown) Therapeutic Significance (Yes, No or Unknown) Notes
EXAMPLE:

Co-deletion of 1p and 18q

EXAMPLE: Yes EXAMPLE: No EXAMPLE: No EXAMPLE:

See chromosomal rearrangements table as this pattern is due to an unbalanced derivative translocation associated with oligodendroglioma (add reference).

Gene Mutations (SNV / INDEL)

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Gene; Genetic Alteration Presumed Mechanism (Tumor Suppressor Gene [TSG] / Oncogene / Other) Prevalence (COSMIC / TCGA / Other) Concomitant Mutations Mutually Exclusive Mutations Diagnostic Significance (Yes, No or Unknown) Prognostic Significance (Yes, No or Unknown) Therapeutic Significance (Yes, No or Unknown) Notes
EXAMPLE: TP53; Variable LOF mutations

EXAMPLE:

EGFR; Exon 20 mutations

EXAMPLE: BRAF; Activating mutations

EXAMPLE: TSG EXAMPLE: 20% (COSMIC)

EXAMPLE: 30% (add Reference)

EXAMPLE: IDH1 R123H EXAMPLE: EGFR amplification EXAMPLE: Yes EXAMPLE: No EXAMPLE: No EXAMPLE: Excludes hairy cell leukemia (HCL) (add reference).

Note: A more extensive list of mutations can be found in cBioportal (https://www.cbioportal.org/), COSMIC (https://cancer.sanger.ac.uk/cosmic), ICGC (https://dcc.icgc.org/) and/or other databases. When applicable, gene-specific pages within the CCGA site directly link to pertinent external content.

Epigenomic Alterations

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Genes and Main Pathways Involved

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Gene; Genetic Alteration Pathway Pathophysiologic Outcome
EXAMPLE: BRAF and MAP2K1; Activating mutations EXAMPLE: MAPK signaling EXAMPLE: Increased cell growth and proliferation
EXAMPLE: CDKN2A; Inactivating mutations EXAMPLE: Cell cycle regulation EXAMPLE: Unregulated cell division
EXAMPLE: KMT2C and ARID1A; Inactivating mutations EXAMPLE: Histone modification, chromatin remodeling EXAMPLE: Abnormal gene expression program

Genetic Diagnostic Testing Methods

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Familial Forms

A subset of cases may develop in the context of ataxia-telangiectasia (AT), which is characterized by germline mutations in the ATM gene. Penetrance of the tumor phenotype is about 10% to 15% by early adulthood.[2] It represents nearly 3% of all malignancies in patients with ataxia-telangiectasia.[3]

Additional Information

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Links

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References

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Notes

*Primary authors will typically be those that initially create and complete the content of a page. If a subsequent user modifies the content and feels the effort put forth is of high enough significance to warrant listing in the authorship section, please contact the CCGA coordinators (contact information provided on the homepage). Additional global feedback or concerns are also welcome.

  1. Matutes, E.; et al. (1991-12-15). "Clinical and laboratory features of 78 cases of T-prolymphocytic leukemia". Blood. 78 (12): 3269–3274. ISSN 0006-4971. PMID 1742486.
  2. Taylor, A. M.; et al. (1996-01-15). "Leukemia and lymphoma in ataxia telangiectasia". Blood. 87 (2): 423–438. ISSN 0006-4971. PMID 8555463.
  3. Li, Geling; et al. (2017-12-26). "T-cell prolymphocytic leukemia in an adolescent with ataxia-telangiectasia: novel approach with a JAK3 inhibitor (tofacitinib)". Blood Advances. 1 (27): 2724–2728. doi:10.1182/bloodadvances.2017010470. ISSN 2473-9529. PMC 5745136. PMID 29296924.