Follicular Lymphoma : Grade 3a
Grade 3 follicular lymphomas (FLs) have greater than 15 centroblasts/hpf. Thus, their spectrum ranges from 16 centroblasts/hpf to cases in which majority of the cells in the neoplastic follicles are centroblasts. Grade 3 FLs are subdivided into 3A (centrocytes still present and admixed with centroblasts) and 3B (solid sheets of centroblasts). The image shows an example of Grade 3A follicular lymphoma. Centroblasts with large round vesicular nuclei and prominent nucleoli make up the dominant cell type; however, centrocytes are still present. Mitotic activity is increased in Grade 3 FLs and their clinical behavior is aggressive.