Comparative immunohistochemical analysis of pediatric Burkitt lymphoma and diffuse large B-cell lymphoma.

Burkitt lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL) account for nearly all pediatric nonlymphoblastic B-cell lymphomas. Because clinical behavior, prognosis, and response to therapy might differ, diagnostic accuracy is important. Morphologic examination often is sufficient, but occasionally, diagnostic ancillary studies are required. In adults, immunophenotyping is useful; however, pediatric data are limited. We characterized the immunohistochemical expression of 6 proteins (c-myc, CD10, bcl-6, bcl-2, CD138, and MIB-1) in pediatric BL (33 cases) and DLBCL (20 cases) with classic morphologic features. Significant differences in c-myc (BL, 30/33 [91%] vs DLBCL, 5/20 [25%]; P < .0001), bcl-2 (BL, 1/25 [4%] vs DLBCL, 7/19 [37%]; P < .02), and mean MIB-1 (BL, 99% vs DLBCL, 56%; P < .0001) expression were observed. There were no significant differences for CD10 (100% expression in BL and DLBCL), bcl-6 (BL, 23/33 [70%] vs DLBCL, 15/20 [75%]), or CD138 (no expression). Thus, pediatric BL and DLBCL have distinctive immunohistochemical profiles, and staining for c-myc, MIB-1, and bcl-2 might be useful in morphologically difficult cases.