University of Virginia Health System

Adult T Cell Leukemia/Lymphoma
(HTLV-1+, ATL-L)

Adult T cell leukemia/lymphoma- Bone marrow aspirate smear, Wright-Giemsa stain, 1000x

Description:

The appearance of the neoplastic cells is essentially diagnostic. The size is quite variable, ranging from medium to large atypical cells resembling Reed-Sternberg cells on Wright-Giemsa stain of the peripheral blood. The cytoplasm is usually basophilic. The nuclear shape is quite variable and often hyperlobated (clover leaf, flower cells). Nuclear chromatin is coarse with variable clumping and nucleoli are usually prominent.

Pathobiology:

Is associated with and probably caused by the human T cell leukemia virus type 1 (HTLV-1). The relationship between this retrovirus and ATL-L comes the closest to fulfilling Koch's postulates for cause and effect between a viral infection and leukemia in humans.

Immunophenotype:

CD3+, CD2+, CD4+, and CD25+, but CD7-, a profile similar to the mycosis fungoides immunophenotype.

Clinical Manifestations and Prognosis:

In the majority of cases the course is aggressive. Although response to chemotherapy is good, response duration is short. In some cases the course is more indolent. Four clinical variants are recognized:

• Acute (ATL-L)
  • Rapid course characterized by leukemia, lymphadenopathy, hepatosplenomegaly, hypercalcemia, lytic bone lesions without evidence of tumor involvement at the site of the lytic lesions, and skin involvement. Median survival 1 year or less.
• Lymphomatous 
  • Course and manifestations similar except less of a leukemic component. Lymphadenopathy prominent. Median survival also 1 year or less. 
• Chronic
  • Less of a leukemic phase and less disseminated. Shin involvement is prominent. Usually progresses to aggressive subtypes in 1-2 years. Median survival 2 years or less.
• Smoldering
  • Usually presents with only to a minimal involvement of the peripheral blood. Skin and pulmonary involvement are the dominant features. Progression to the more aggressive subtype is less frequent and often after a much longer course. 

General References:

• Jaffe ES, Harris NL, Stein H, Vardiman JW, eds. Pathology and genetics of tumors of hematopoietic and lymphoid tissues. Vol. 3 of World Health Organization classification of tumors. Lyon, France: IARC Press, 2001
• Shimoyama M. Diagnostic criteria and classification of clinical subtypes of adult T-cell leukemia-lymphoma. Br J Haematol 79:428, 1991