Undifferentiated non-Hodgkin's lymphomas (Burkitt's and non-Burkitt's types). The relevance of making this histologic distinction.

A retrospective study of 66 cases of undifferentiated non-Hodgkin's lymphomas at the National Cancer Institute over a 22-year period suggests that the histologic distinction between Burkitt's and non-Burkitt's types is clinicopathologically meaningful. Thirty-nine patients with Burkitt's lymphoma had a median age at presentation of ten years. The primary site of disease in these patients was more commonly extranodal; at the time of diagnosis 26 (66%) of these cases revealed intra-abdominal involvement; 25 (64%) of the cases were Stage IV. The 27 patients with non-Burkitt's lymphomas had a median age at presentation of 34 years; the primary site of disease was more commonly nodal (peripheral adenopathy was often present at the time of diagnosis); only nine (33%) of the cases were Stage IV. Median survival was essentially equivalent in the two groups, 9.5 months for Burkitt's lymphoma and 10.0 months for the non-Burkitt's lymphoma. Overall, survival was not significantly different among the two patient populations; however, patients with Burkitt's lymphoma had a longer survival than those with non-Burkitt's lymphoma. Estimates of five-year survival (with 95% confidence) are 42% for Burkitt's lymphoma and 11% for non-Burkitt's lymphoma, respectively, which are significantly different (P = 0.01).