Lymphomas, T/NK-Cell - T/NK-Cell Lymphomas

Diagnosis

Indications for Testing

• Elevated white blood cell count and lymphocytes
• Abnormal manual differential results

Laboratory Testing

• Absolute lymphocytosis >4,000/μL or abnormal morphology – phenotyping by flow cytometry
  • Positive finding with aberrant T-cell or NK-cell phenotype
    • At least one of the following positive: CD56, CD57, CD16 – large granular lymphocytic leukemia (LGLL)
      • CD3+  – T-cell LGLL
        • Follow-up with T-cell clonality testing
      • CD3-  – NK-cell LGLL
    • Negative CD57, CD56, and CD16
      • CD10+, CD4+  – angioimmunoblastic T-cell lymphoma
      • CD4+/-, CD8+/-  – consider peripheral T-cell lymphoma, not otherwise specified (NOS)
      • CD30+  – consider anaplastic large-cell lymphoma
      • CD4+, CD7, CD26 – consider Sézary syndrome 
  • No positive finding – consider reactive lymphocytosis
    • Consider other etiologies
    • Viral (Epstein Barr virus, cytomegalovirus, human immunodeficiency virus,  human T-lymphotrophic virus type 1, hepatitis, human herpesvirus 8)
    • Other (tuberculosis, Rickettsia, brucella, toxoplasmosis, syphilis, Babesia microti)
• Apparent reactive cause (infection, postsplenectomy) – manage cause and recheck white blood cell count
  • Unexplained persistence – phenotyping by flow cytometry (see above)

Histology

• Bone marrow biopsy
  • Goal – ≥2 cm length
  • Classified as involved or not
  • Flow cytometry may be helpful in classification
  • Some reactive T-cell infiltrates, especially in the skin, may be negative for CD7 in many of the cells
• Immunophenotyping to identify the malignancy of lymphoid proliferation and to categorize the lymphoma
  • Flow cytometry testing by identification of aberrant antigen expression patterns (ie, loss of one or more pan-T-cell antigens or coexpression of CD10)
  • Markers – kappa, lambda, CD2, CD3, CD4, CD5, CD7, CD8, CD10, CD16, CD19, CD20, CD23, CD25, CD26, CD30, CD45, CD56, CD57, CD103
• Immunohistochemistry
  • Stains – CD1a, CD2, CD3, CD4, CD5, CD7, CD8, CD10, CD15, CD21, CD23, CD25, CD30,  CD34, CD43, CD45RO, CD56, CD57, Ki-67, EBER-EBV, ALK, BF-1, Muc-1, TIA-1, granzyme B, TdT
  • Others available – CD20, CD45RA-MT2, CD95, BCL-2, c-Myc
  • Mycosis fungoides/Sézary syndrome – skin biopsy (see topic for specific markers)

Imaging Studies

• CT/MRI – most useful in assessing where disease is present after diagnosis

Prognosis

• International Prognostic Index scoring system
  • Based on pretreatment clinical factors of age (≤60 years); tumor stage (I or II); number of extranodal sites (≤1); ECOG performance status (0 or 1); and serum lactate dehydrogenase (LD) (≤1 times normal) – all scored as 0
  • Patients placed in 4 risk groups
  • Limited usefulness in follicular lymphoma, mantle cell lymphoma, NK-cell lymphoma, nasal-type, hepatosplenic lymphoma, and enteropathy-type lymphoma
• Other prognostic systems include
  • Prognostic index for peripheral T-cell lymphoma not otherwise specified – uses bone marrow involvement, age, performance status, LD
  • Bologna score – uses immunohistochemistry (CD15, EBV, Ki76)
  • Korean prognostic NK-cell score – uses B symptoms, LD, stage, regional node involvement
  • NK prognostic score – uses stage, performance status, extranodal involvement, nasal type (non vs (+))

Differential Diagnosis

• Lymphomas
  • B-cell lymphoma
  • Hodgkin lymphoma
• Reactive lymphocytosis
• Sarcoidosis
• Other malignancy
  • Head and neck cancer
  • Metastatic cancer
• Infections
  • Epstein-Barr virus
  • M. tuberculosis
  • Bartonella spp
  • Human herpesvirus 8
  • HTLV1
  • Cytomegalovirus
  • HIV
  • Toxoplasma gondii
  • Treponema pallidum
  • Babesia microti
  • Fungal disease

Clinical Background

T-cell and NK-cell non-Hodgkin lymphomas (NHL) represent a small portion of the lymphomas diagnosed in the U.S.

Epidemiology

• Incidence – 15-20% of all NHL lymphomas
  • ~70,000 NHL diagnosed annually
• Age – usually adults (incidence increases with age)
• Sex – unequal distribution; based on specific type

WHO Classification of Mature T- and NK-cell Neoplasms (2008)

• T-cell prolymphocytic leukemia
• T-cell large granular lymphocytic leukemia
• Chronic lymphoproliferative disorder of NK-cells (provisional entity)
• Aggressive NK-cell leukemia
• Systemic Epstein-Barr virus (EBV)-positive T-cell lymphoproliferative disorder of childhood
• Adult T-cell leukemia/lymphoma (ATLL)
• Extranodal NK/T-cell lymphoma, nasal type
• Enteropathy-associated T-cell lymphoma
• Hepatosplenic T-cell lymphoma
• Subcutaneous panniculitis-like T-cell lymphoma
• Mycosis fungoides
• Sézary syndrome
• Primary cutaneous CD30-positive T-cell lymphoproliferative disorders
• Primary cutaneous gamma-delta T-cell lymphomas
• Peripheral T-cell lymphoma, NOS (not otherwise specified)
• Angioimmunoblastic T-cell lymphoma
• Anaplastic large-cell lymphoma (ALCL), ALK positive
• ALCL, ALK negative (provisional entity)

Risk Factors

• Viral infection
  • Human T-lymphotropic virus type 1 (HTLV1) – ATLL
  • EBV – nasal NK-cell lymphomas
• Chromosomal rearrangements
  • Predominantly on T-cell receptor (TCR) genes
• Host susceptibility factors – congenital or acquired
  • Gliadin allergy – enteropathy-type T-cell
  • Immunosuppression

Clinical Presentation of Selected Lymphoma Subtypes (based on WHO classification)

• Precursor T-cell neoplasm
  • Precursor T-lymphoblastic lymphoma/leukemia

    Incidence – rare, 2% of non-Hodgkin lymphomas Age – median is 20 years Sex – M>F Symptoms – frequent infection, lymphadenopathy, mediastinal masses Prognosis – good

• Mature T-cell and NK-cell neoplasms
  • T-cell prolymphocytic leukemia

    Incidence – rare, 2% of mature lymphocytic leukemias Age – median is 65 years Symptoms – lymphadenopathy, hepatosplenomegaly

    T-cell large granular lymphocyte leukemia

    Incidence – rare, 2-3% of mature lymphocytic leukemias Age – majority 45-75 years, rare <25 years Sex – M:F, equal Symptoms – lymphadenopathy rare; symptoms related to bone marrow involvement Prognosis – indolent course

    Chronic lymphoproliferative disorder of NK cells

    Incidence – rare Age – median is 60 years Sex – M:F, equal Symptoms – persistent increase in blood NK cells (over period >6 months); may be asymptomatic or have cytopenias or systemic symptoms Must exclude reactive causes Prognosis – usually indolent but may have progressive cytopenias, immune dysfunction

  • Aggressive NK-cell leukemia

    Incidence – rare, almost always associated with Epstein-Barr virus Age – median is 42 years Sex – M:F, equal Ethnicity – more common in Asians Symptoms – fever, cytopenias Prognosis – poor, aggressive course

  • Adult T-cell leukemia/lymphoma (ATLL)

    Distinct T-cell lymphoma associated with human T-lymphotropic virus type 1 (HTLV1) Prevalence – 15-20 million globally infected with HTLV1 Endemic in Japan, Caribbean and South American countries, and sub-Saharan Africa Age – median is 58 years HTLV1-associated myelopathy (HAM)/tropical spastic paraparesis (TSP) – 30s-40s Sex Adult T-cell leukemia/lymphoma – M>F HAM/TSP – M<F Transmission Parenteral Sexual Classified into 4 subcategories – smoldering, chronic, lymphoma, acute Smoldering and chronic – considered indolent Lymphoma – ≤1% abnormal T-lymphocytes, histologically proven lymphadenopathy, no lymphocytosis Acute – leukemic manifestation and tumor lesions; rapidly progressive course

    Extranodal NK/T-cell lymphoma, nasal type

    Incidence – rare; associated with Epstein-Barr virus Sex – M>F Ethnicity – more common in South America (particularly native American population) and Asia Symptoms – nasal symptoms, palate lesions, skin lesions Prognosis – usually aggressive

    Enteropathy-associated T-cell lymphoma

    Incidence – rare, associated with celiac disease Symptoms – much like celiac disease Prognosis – poor, recurrence frequent

    Hepatosplenic T-cell lymphoma

    Incidence – rare, 20% occur in setting of chronic immunosuppression (particularly in Crohn disease) Age – 20s Sex – M>F Symptoms – hepatomegaly with bone marrow involvement often manifested as thrombocytopenia

  • Subcutaneous panniculitis-like T-cell lymphoma

    Incidence – rare, <1% of non-Hodgkin lymphomas Age – median is 35 years Sex – M<F Symptoms – nodular lesions below area of arms, legs and/or trunk; up to 20% have associated autoimmune disease Prognosis – moderately good

  • Mycosis fungoides/Sézary syndrome

    Incidence – 1/100,000 Age – mean is 60 years Sex – M>F, 2:1 Classification – most common is mycosis fungoids; next most common is primary cutaneous lymphoproliferative disorders Symptoms – usually manifest with history of persistent skin disease preceding diagnosis Prognosis – variable, usually indolent until tumoral stage or systemic disease develops Sézary syndrome is an aggressive leukemic form of mycosis fungoides with a poor prognosis

    Primary cutaneous CD30-positive T-cell lymphoproliferative disorders

    Incidence – rare Age – median is 60 years, majority >30 years Sex – M>F, 2-3:1 Symptoms – nodules; plaques with necrosis and ulceration most commonly on face, trunk, and extremities Prognosis – aggressive with poor prognosis if CD8+ or alpha-beta+

    Peripheral T-cell lymphoma, unspecified type

    Incidence – 30% of peripheral T-cell lymphomas, 5-7% of non-Hodgkin lymphomas Age – median is 60 years Sex – M>F, 2:1 Genetics – TCR clonality is rarely positive Symptoms – fever, nodal enlargement, extranodal involvement Prognosis – aggressive course with liver and spleen involvement in >50% of cases

    Angioimmunoblastic T-cell lymphoma

    Incidence – 15-20% of T-cell lymphomas, 4-6% of non-Hodgkin lymphomas Age – peak is 70 years Sex – M:F, equal Genetics – TCR clonality positive Symptoms – fever, skin rash, arthritis, autoimmune hemolytic anemia, eosinophilia, extranodal site involvement Prognosis – aggressive tumor with poor prognosis

    Anaplastic large-cell lymphoma (ALCL), ALK positive

    Incidence – 2-3% of non-Hodgkin lymphomas in adults, 10-20% of childhood lymphomas Age – mean is 35 years; includes nearly all pediatric cases Sex –  M>F, 3:1 Genetics – over-expression of ALK due to specific translocations, most common is t(2;5) or NPM-ALK translocation (40-60% of patients) Symptoms – often presents with extranodal disease Prognosis – overall 5-year survival rate ~70% for ALK-positive (49% for ALK-negative) Tendency to late relapses – relapses often respond to additional therapy

    ALCL, ALK negative

    Similar morphology and immunophenotype as ALK-positive ALCL without ALK over-expression Age – 40-65 years Sex – M>F, 1.5:1 Genetics – majority of cases show clonal rearrangement of TCR Symptoms Advanced stage III-IV disease Peripheral and/or abdominal lymphadenopathy B symptoms – fever, weight loss Prognosis – poor response to therapy Favorable (90%) survival rate for primary cutaneous ALCL despite being negative for ALK1 protein

Indications for Laboratory Testing

• Tests generally appear in the order most useful for common clinical situations
• Click on number for test-specific information in the ARUP Laboratory Test Directory

Click the plus sign to expand the table of additional tests.

Test Name and Number	Comments
CD20, L26 by Immunohistochemistry 2003532 Method: Immunohistochemistry
BCL-2 by Immunohistochemistry 2004513 Method: Immunohistochemistry
Potassium, Plasma or Serum 0020002 Method: Quantitative Ion-Selective Electrode
Calcium, Ionized, Serum 0020135 Method: Ion-Selective Electrode/pH Electrode
Phosphorus, Inorganic, Plasma or Serum 0020028 Method: Quantitative Spectrophotometry

Diagnostic Algorithm

  Lymphoma Leukemia Phenotyping Testing Algorithm