[The ultrastructure of megathrombocytes in May-Hegglin's anomaly]

A clinical and extensive electron microscopic study was made of the circulating granulocytes and thrombocytes from three female patients of a family with May-Hegglin anomaly. There have been observed inclusion bodies (Döhle-bodies) in a high proportion of polymorphonuclear leukocytes as well as a thrombocytopenia and giant platelets (so-called megathrombocytes). Other family members did not show hematologic abnormalities. The investigated giant platelets show ultrastructurally a different electron density of the alpha-granules, however, these structures present no typical formation of "bull's eye granules" which has been observed in other cases of May-Hegglin anomaly. Peripheral or central situated net-like structures of the endoplasmic reticulum have been found frequently. There were seen no microtubuli whereas glycogen particles were scattered within the peripheral cytoplasm.