Represents approximately 20 percent of T-cell lymphomas and 1 percent of all lymphomas.
Median age of onset approximately 65 years. Males are affected slightly more often than females.
Two types can occur: one evolving from angioimmunoblastic lymphadenopathy with dysproteinemia and the other arising de novo.
Lymph node histopathology is characterized by nodal effacement and loss of germinal centers with a pleomorphic cellular infiltrate that in addition to neoplastic T cells has a background of plasma cells, immunoblasts, eosinophils, and macrophages. Small arborizing blood vessels are an important and prominent feature in the node.
The neoplastic cells are CD4+ αβ T cells with β or γ T-cell receptor rearrangement (CD4+ follicular helper T cells). Pan T-cell markers are evident (e.g., CD2, CD3, CD5).
The neoplastic T cells express CD10 in about 90 percent of cases, a marker characteristic of this type of lymphoma.
CD8 cellular staining is present, but on reactive T cells in the background.
Immunoglobulin gene rearrangements may be found in 20 percent of cases; but, they represent expanded clones of Epstein Barr virus-carrying B cells.
Epstein-Barr virus-positive B cells are frequently present scattered throughout the node and is thought to be a secondary infection related to immunodeficiency.
Patients present with widespread lymphadenopathy and splenomegaly with frequent involvement of marrow, liver, and skin. Pruritus may accompany the rash.
Fever, night sweats, weight loss are very common at diagnosis.
Pleural and peritoneal effusions (ascites) and arthritic manifestations may be present.
Laboratory abnormalities include polyclonal hypergammaglobulinemia, immune complexes, cold agglutinins, rheumatoid factor, and other anti-tissue antibodies.
The most frequent cytogenetic abnormalities are trisomy 3, trisomy 5, and involvement of the X chromosome. Complex karyotypes are a poor prognostic sign.
Most patients are treated with anthracycline antibiotic-containing multidrug regimens. As in most other T-cell lymphomas, the initial response rate is about 40 percent, but survival is not extended significantly by such treatment.
The course is usually aggressive and median survival is approximately 3 years.
Poor prognostic signs are male sex, mediastinal lymphadenopathy, anemia, and complex cytogenetic patterns at the time of diagnosis.
Large B-cell lymphoma may supervene, often Epstein Barr virus-positive.