T-cell non-Hodgkin lymphoma (NHL) represents a small portion of lymphomas diagnosed in the U.S.

Epidemiology

• Incidence - 10-15% of all lymphomas
  • 55,000-60,000 lymphomas diagnosed each year
• Age - increased incidence in older patients
• Gender - unequal distribution based on specific type

Classification

Risk Factors

• Viral infection with HTLV 1
• Chromosomal rearrangements
  • Predominantly on T-cell receptor gene (TCR)

Selected specific T-cell lymphomas

• Peripheral T-cell lymphoma
  • Incidence - 50-60% of T-cell lymphomas, 5-7% of NHL
  • Gender - M:F; 1.5:1
  • Age - median 60 years
  • Genetic - TCR clonality is rarely positive
  • Symptoms - fever, nodal enlargement, increased liver tests, extranodal involvement
  • Prognosis - moderately good
• Angioimmunoblastic T-cell lymphoma
  • Incidence - 15-20% of T-cell lymphomas, 4-6% of NHL
  • Gender - equal distribution
  • Age - onset 50-60 years
  • 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 - T-/null-cell type
  • Incidence - 2-3% of NHL
  • Gender
    • ALK (+) - M:F; 3:1
    • ALK (­) - M:F; 0.9:1
  • Age
    • ALK (+) - mean, 35 years and nearly all pediatric cases
    • ALK (-) - mean,  7th decade
  • Genetics - expression of anaplastic lymphoma kinase (ALK)
  • Symptoms
    • ALK (-) is usually nodal disease
    • ALK (+) often presents with extranodal disease
  • Prognosis - poor with ALK negative disease but moderate with ALK positive
• Cutaneous T-cell and NK-cell Lymphomas
  • Incidence - rare
  • Age - patients tend to be older
  • Symptoms - usually manifests with history of persistent skin disease preceding diagnosis    
  • Prognosis - variable, usually indolent until tumoral stage or systemic disease develops

Refer to T-cell Lymphomas topic at www.arupconsult.com for a chart of Cutaneous T-cell and NK-cell Lymphomas

Diagnosis

• Laboratory testing
  • See the Leukemia Lymphoma Phenotyping Testing algorithm for specific test ordering recommendations
  • Immunophenotyping to identify the malignancy of the 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 co-expression of CD10)
    • Some reactive T-cell infiltrates, especially in the skin, may be negative for CD 7 in many of the cells
  • T-cell clonality studies to identify clonal rearrangements of the T-cell receptor gene - Southern blot or PCR testing