Diffuse large B-cell lymphomas (DLBCL) are composed of large or medium-sized neoplastic B cells (large noncleaved cells) whose nuclei are slightly larger than a histiocyte nucleus or more than twice the size of a small lymphocyte. These large neoplastic cells can be subdivided into centroblasts, immunoblasts, and anaplastic types. Lymphomas with >90% immunoblasts are considered immunoblastic; the remainder (with <90% immunoblasts) are classified as centroblastic (large noncleaved cell variant). Most cases contain a mixture of the two main cell types. Given the low intraobserver and interobserver reproducibility, it is not considered necessary to subtype DLBCL into centroblastic and immunoblastic subtypes. Centroblasts have round, angular, or multilobated vesicular nuclei, multiple small peripheral nucleoli, and a thin rim of amphophilic cytoplasm. This image shows mostly centroblasts with scattered small lymphocytes (which are mostly T-cells). In addition, there may be histiocytes, plasma cells and neutrophils.