Peripheral blood showed agranular platelets with variable size (A, Wright stain, 1000×). Bone marrow touch preparation showed a megakaryocyte with prominent (B, Giemsa stain, 1000×). Bone marrow biopsy showed normocellular bone marrow (70%) with trilineage hematopoiesis and frequent emperipolesis in megakaryocytes (C, hematoxylin and eosin stain, 400×; inset, 1000×). The CD61 stain highlights megakaryocyte emperipolesis (D, immunohistochemistry with hematoxylin counterstain, 1000×).