SOME PROBLEMS ON THE HISTOPATHOLOGICAL DIAGNOSIS OF NON‐HODGKIN'S MALIGNANT LYMPHOMA— A Proposal of a New Type—

Abstract
A new classification for non‐Hodgkin's malignant lymphoma is proposed as the one suited for the Lymphomas in Japan, which is to provide a new subtype “pleomorphic” for those more or less rapid‐growing lymphomas of peripheral T‐cell nature, along with another subtype lymphoblastic, after Nathwani et al. for those of central T‐cell nature. The proposal is based on the result of the investigation by the Study Group for Histopathological Diagnosis on Malignant Lymphoma that (1) the presence of a significant number of T‐cell lymphomas with peculiar “pleomorphism” is responsible for the very low reproducibility rate of histopathological diagnosis on the diffuse, mixed L&H type of Rappaport classification, and (2) the relative incidence of lymphoms of peripheral T‐cell nature including the so‐called adult T‐cell leukemia is much higher in Japan than in the Western countries.