T-lymphoblastic and peripheral T-cell lymphomas in the northern part of The Netherlands. An immunologic study of 29 cases.

The morphologic type, immunophenotypes, and clinical presentation of 12 cases of T-lymphoblastic lymphoma and 17 cases of peripheral T-cell lymphoma were studied. The lymphoblastic cases were subclassified according to intrathymic stages of T-cell differentiation. Two cases had an early intrathymic immunophenotype (CD4-negative, CD8-negative, CD1-negative), seven cases had an intermediate intrathymic immunophenotype (CD1-positive, CD4-positive, CD8-positive), and two cases had a late intrathymic immunophenotype (CD1-positive, CD8-positive, CD4-negative); one case expressed T-cell and B-cell markers. The peripheral T-cell lymphomas were morphologically subclassified according to the updated Kiel classification. T-cell lymphomas of low-grade malignancy--chronic lymphocytic lymphoma, T-zone lymphoma, and pleomorphic small cell lymphoma--in general had a complete immunophenotype matching the immunophenotypes of normal peripheral T-cells. In addition these cases were CD38-positive and HLA class II-positive. The T-cell lymphomas of high-grade intermediate and large cell, immunoblastic and large cell anaplastic lymphoma--were characterized by loss of T-cell markers. For their establishment as T-cell lymphoma a panel of monoclonal antibodies is needed.