Bone marrow from thrombocytopenic individuals contains small megakaryocytes with decreased nuclear complexity.

Photomicrographs of bone marrow aspirates are shown after Wright-Giemsa staining (magnification, 750 ×). (A) A representative megakaryocyte from an unaffected individual (IV-8). (B-D) The characteristic morphology of megakaryocytes seen in 2 thrombocytopenic individuals (IV-10 and V-14).