Malignant lymphoma with a high content of epithelioid histiocytes.A distinct clinicopathologic entity and a form of so-called „Lennert's Lymphoma”

Abstract

Detailed pathologic and clinical findings in 19 patients with malignant lymphoma with a high content of epithelioid histiocytes (MLEH) are presented. The essential morphologic features for inclusion in this study comprised a diffuse architectural pattern; obliteration of normal nodal architecture; small, poorly defined clusters of epithelioid cells scattered throughout the stroma; and proliferation of atypical small and large lymphoid cells in varying proportions. Males predominated and the patients' ages ranged from 23 to 75 years, with a median age of 49 years. All patients had cervical adenopathy. Generalized adenopathy and splenomegaly occurred in approximately half. Hepatomegaly was less frequent, but the liver was histologically involved in four of seven patients in whom biopsies were performed. Skin rashes developed in two, but Waldeyer's ring involvement was noted in only one patient. More than half of these patients had „B” symptoms. Staging procedures disclosed that 74% were pathologic Stage IV. In seven surgically staged patients, the histologic features in the initial diagnostic lymph node biopsy were reproduced in the involved tissues at laparotomy. All patients received a variety of single agent and/or combination chemotherapy. Four patients received radiotherapy in addition to chemotherapy. The median survival was 15.6 months. Thirteen patients have died, all with clinical evidence of residual lymphoma. The cause of death in six was infection. In two of the four autopsies, the epithelioid cell component was absent and the microscopic features were indistinguishable from diffuse lymphoma of mixed cell type. While this disorder shares certain clinical and histologic features with Hodgkin's disease and with angioimmunoblastic lymphadenopathy, our observations lead us to the conclusion that MLEH, as defined in this paper, should be considered a variant of a non-Hodgkin's lymphoma and a distinct clinicopathologic entity.