Typical morphology of Burkitt leukemia. Characteristic immunophenotype is illustrated by flow cytometric analysis: CD10⁺, CD19⁺, CD20⁺ (bright), surface immunoglobulin light chain λ restricted (bright) and CD5^–. Peripheral blood involvement by BL (H&E stain) was photographed using the Olympus model BX50 microscope (Olympus UPlanF1 100X/1.30 oil). Photography was performed with the digital camera MTI model 3CCD, PAXit version 2.0 software, and Adobe Photoshop 7.0 imaging processing. For the flow cytometry inserts, data was acquired using a Coulter FC500 instrument (Beckman-Coulter, Fullerton, CA) with XCP version 1.2 analysis software (Beckman-Coulter).