Megakaryocyte clusters and atypical morphology. (Left) Megakaryocyte clusters were a common finding, original magnification ×400. (Right) Cytologically atypical megakaryocytes with abnormal nuclear segmentation and visible nucleoli. Photomicrographic images were obtained with an Olympus BX51 microscope equipped with an Olympus DP71 camera and software. Original magnifications: left panel, 40×/1.30 oil UPlanFL N lens; right panel, 100×/1.40 oil UPlanS Apo lens.