A morphologic study of childhood lymphoma of the lymphoblastic type. The pediatric Oncology Group experience

For this study 227 non-Hodgkin's lymphomas, registered through the Pediatric Oncology Group clinical studies between 1976 and 1982, were morphologically subclassified into major histologic types and subtypes, and their histopathologic and clinical features were compared. These lymphomas were distributed primarily into only three of the recognized major histologic types: lymphoblastic (LB), 106 (47%); undifferentiated (DU), 49 (21%); and diffuse histiocytic (DH), 72 (32%). These patient groups were found to differ in several ways: the LB lymphomas contained most of the patients under two years of age; the LB lymphomas tended to present in higher clinical stages; the LB lymphomas tended to involve lymph node groups and the bone marrow more often than did the DU and DH lymphomas; and the DU lymphomas had a greater tendency for gastrointestinal tract and other major organ system involvement. The complete remission rate of 96%, for the LB lymphomas was better than for either the DU or the DH lymphomas. The disease-free survival of the LB lymphomas was significantly better than the DU group, but not the DH group. The LB were histologically divisible into three subtypes: convoluted (C), nonconvoluted (NC), and large cell variant (LCV). The C and NC subtypes preferentially involved the mediastinum and peripheral lymph nodes initially, while the LCV tended to involve the abdomen. However, none of the subtypes differed in clinical stage. The complete remission, and the disease-free survival rates between these subtypes were not statistically different.