Small noncleaved follicular center cell (FCC) lymphoma: Burkitt and non-Burkitt variants in the United States. I. Clinical features.

With the understanding that Burkitt's lymphoma was of follicular center cell (FCC) derivation, Lukes and Collins classified the tumor, descriptively, as small noncleaved FCC lymphoma. Two subtypes were described: Burkitt and non-Burkitt. Attempting to define the clinicopathologic features of the subtypes, we studied 42 patients: 25 Burkitt and 17 non-Burkitt. Histologically, the Burkitt tumor demonstrated remarkable uniformity of nuclear size and contour, whereas the non-Burkitt variant had greater variability. Immunoglobulin monoclonality was demonstrated in 83% of Burkitt and 81% of non-Burkitt cases. Burkitt patients tended to be younger. Gastrointestinal disease was seen in 15 Burkitt and only four non-Burkitt patients (P less than 0.05). Disseminated disease was found in the majority of both variants. Marrow involvement was demonstrated in 4.5% of Burkitt and 37.5% of non-Burkitt patients (P less than 0.05). Median survival of Burkitt patients was 10.5 months versus 7.7 months in the non-Burkitt group. The authors believe that significant biologic differences between the variants have been demonstrated, which may be of potential value to the clinician.