Thirty cases of immunologically determined and histologically diagnosed immunoblastic lymphadenopathy (IBL), angioimmunoblastic lymphadenopathy (AILD), and IBL-like T-cell lymphoma were clinicopathologically reviewed. Clinical manifestations and laboratory findings did not reveal significant differences in these three groups. IBL, AILD, and IBL-like T-cell lymphoma showed a spectrum of histologic changes, in which proliferation of pale cells was a critical diagnostic point for the histologic malignancy. Immunostaining for their subsets revealed that 3 of 21 cases showed T4+ phenotype and the remaining 19 cases showed T8+ phenotype. Three of seven immunohistochemically determined T8+ cases simultaneously expressed Leu7+ phenotype. The latter cells were consistent with large granular lymphocytes in one case, but no clinicopathological differences from the other T8+ cases were present. IBL and AILD were considered to be T-cell malignancies, which show a spectrum of histologic features from T-cell dysplasia to peripheral T-cell lymphoma (IBL-like T-cell lymphoma). Despite intensive chemotherapy, prognosis was poor in T8+ cases of which half of the patients died within 1 year. T4+ cases showed better prognosis, but a higher incidence of synchronous second primary cancers was recognized.