LOCALIZED GASTRIC NON-HODGKINS-LYMPHOMA OF HIGH-GRADE MALIGNANCY IN PATIENTS WITH PREEXISTING CHRONIC LYMPHOCYTIC-LEUKEMIA OR IMMUNOCYTOMA

Analyses for clonality in cases of Richter's syndrome have provided ev idence for a clonal evolution of high-grade lymphoma in most patients, while in others an independent cellular clone seems to exist in the s econdary neoplasm. Richter's syndrome with an isolated high-grade lymp homa of the stomach has been rarely reported in patients with pre-exis ting B cell chronic lymphocytic leukemia (CLL). We investigated four c ases of CLL or lymphoplasmacytoid immunocytoma (LPIC) with development of a localized high-grade B cell lymphoma in the stomach. Southern bl otting showed different rearrangements of the immunoglobulin light and heavy chain genes in the tumor cells of the low-grade lymphoma and th e gastric tumor in two cases. Comparison of the DNA sequences of the C DR3 region of the immunoglobulin genes revealed different clones in an other case. By means of chromosomal in situ hybridization, trisomy 3 w as detected in two cases of high-grade lymphoma of the stomach, but no t in the cells of the associated low-grade tumor. Our findings indicat e that high-grade non-Hodgkin's lymphomas arising localized in the sto mach of patients with CLL or immunocytoma are not clonally related to the pre-existing low-grade lymphoma and, therefore indeed, present tru e secondary neoplasms.