Peripheral T cell lymphoma in adults: morphological and phenotypical study of four cases.

In the present study we investigated the lymph node morphology and distribution of cell surface phenotypes in four cases of adult peripheral T cell lymphoma. Histologically, the tumors were classified as T zone lymphoma, T cell lymphoma with large multilobated nuclei and T cell immunoblastic sarcoma. In the T zone lymphoma the neoplastic lymphocytes were E+ (90%) and exhibited intensive focal staining for acid phosphatase (93%) and acid esterase (92%); the phenotype distribution revealed low expression of the T-3 antigen (49%), selective expression of the T-4 antigen (72%) and poor expression of T-6 (10%) and T-10 antigens (22%). Some of these features are present in normal and in neoplastic immature T cells. In the remaining three cases the majority of lymph node cells were E+ (59-75%), T-3+ (67-80%) and T-8+ (43-55%). A distinctive feature of the T cell immunoblastic sarcoma was the presence of high percentages of DR+ cells (62%; 63%). Thus our results indicate that the morphological heterogeneity of peripheral T cell lymphoma is also paralleled by a variety of surface phenotypes and that phenotype studies may provide a useful contribution to identification and accurate classification of peripheral T cell neoplasms.