|Photomicrograph of T-lymphoblastic lymphoma. Click to enlarge.
||Photomicrograph of T-lymphoblastic lymphoma. Click to enlarge.
T-lymphoblastic leukemia is different from lymphoma in that the leukemia variant should have more than 25% lymphoblasts in normocellular bone marrow. The leukemia variant occurs as frequently as the lymphoma variant.
T-lymphoblastic lymphoma is 10 times more frequent than B lymphoblastic lymphoma and occurs most commonly in teenagers or young adults. The most common manifestation is a large tumor in the anterior mediastinum. Morphologically, cells are moderately large with blast-like nuclei and sparse cytoplasm. Immunohistochemically, the cells are positive for TdT, CD1, CD3 and often CD7. There may be coexpression of CD4 and CD8. Histologically, the cells may be difficult to differentiate from thymus cells, possibly as part of a thymoma. This applies particularly to small biopsies, therefore, biopsies as large as possible should be sent for diagnostics.
This is a rapid-growing form of lymphoma. Patients become quickly increasingly affected by the disease and it is important to start treatment immediately.
The time from finished primary treatment to recurrence is important for the prognosis.
The induction regimen for acute lymphoblastic leukemias is followed (Hammersmith 82 or ALL-Therapistudie des Erwachsenen 05/93). Instead of maintenance treatment with mainly oral chemotherapy over 1.5–3.5 years, patients can alternatively be offered consolidative treatment with HDT with SCS in the first remission. This treatment gives 3-year recurrence-free survival in more than 50% of patients. One disadvantage of this treatment is the increased risk for infertility.
With recurrence in patients who have undergone HDT with SCS in the first remission, the treatment goal is palliative. Patients with recurrence after maintenance treatment should be evaluated for high-dose treatment with allogeneic stem cell transplantation in the second complete remission.