Morphological, immunophenotypic, and genetic features of triple-positive DLBCLs. (A) B-cell lymphoma with blastic morphology characterized by medium- to large-sized cells with irregular nuclei, fine chromatin, inconspicuous nucleolus, and scant cytoplasm (case 10), (original magnification ×400; hematoxylin and eosin stain). (B-G) Case 5 shows a characteristic centroblastic morphology (original magnification ×400; hematoxylin and eosin stain). The tumor cells are CD10+ (C), MUM1/IRF4+ (D), and BCL6+ (E) (original magnification ×400; immunostaining). FISH demonstrates an IRF4 (F) and IGL (G) break with 1 colocalized signal (yellow arrow) and 1 split signal (green and red arrows) consistent with gene rearrangement. (H) In case 2, an IGK break was demonstrated. FISH shows a signal constellation of 1 colocalized signal (yellow arrow) and 1 split signal (green and red arrows) consistent with gene rearrangement.