Cytogenetic studies in malignant lymphomas: a study of 8 cases.

Chromosome studies were carried out, by a direct method, in 28 subjects with malignant lymphomas. Lymph node cells were analysed in 24, ascitic fluid sediments in 3 and bone marrow cells in 1. Chromosome abnormalities, both numerical and structural, were found in 12 of 14 cases of well differentiated and poorly differentiated lymphocytic lymphomas, and reticulum cell sarcomas, and in 8 of 14 cases with Hodgkin's disease. The karyotypes were different from case to case and there was no correlation with the histology. In individual cases the abnormalities followed a clonal pattern indicating a common precursor for the abnormal cells. The modal number of chromosomes was near-diploid in the lymphocytic lymphomas and reticulum cell sarcomas.Hodgkin's disease showed two main features; a predominant population of cells with normal karyotype accompanied by a small number of cells of an abnormal clone with a predominantly hypertriploid number of chromosomes. It is suggested that the first population represents mitoses in the surrounding lymphocytes. Its cytogenetic normality is an argument against its neoplastic origin, and they could be components of an inflammatory reaction, the true neoplastic cells being the abnormal reticulum cells.