IV.A.001

Bernard-Soulier disease. Blood film. Note large platelets. Some giant-sized platelets are the diameter of red cells with a range from slightly enlarged (one-third the diameter of a red cell) to enormous.

IV.A.002

Gray platelet syndrome (α-granule deficiency). Blood film. The platelets are characteristically larger than normal and are pale gray forms. Although thrombocytopenia may occur that is not the case in this example.

IV.A.003

Gray platelet syndrome (α-granule deficiency). Blood film. Periodic acid Schiff stain. The platelets are characteristically larger than normal. This agranular giant platelet stains for glycogen (pinkish-red) (arrow) as does normal neutrophil.

IV.A.004

Gray platelet syndrome: Transmission electron microscopy. (A) Normal platelets. (B) Gray platelet syndrome. Note absence of α-granules, which imparts a bland gray appearance to platelets in the blood film. Occasional radio-opaque bodies are dense bodies. The platelets are rich in glycogen granules and are strongly periodic acid Schiff positive.

IV.A.005

May-Hegglin anomaly. A characteristic giant platelet. An abnormal neutrophil with classic gray-blue inclusions. Patients have a mutation of the MYH9 gene at chromosome region 22q12-13. The mutation results in disordered production of non-muscle myosin heavy-chain type IIA. This leads to macrothrombocytopenia, secondary to defective megakaryocyte maturation and fragmentation. Thrombocytopenia occurs in almost all patients, but severe bleeding is unusual. Individuals may bruise easily, and they may have recurrent epistaxis, gingival bleeding, menorrhagia, or excessive bleeding associated with surgical procedures. The neutrophil inclusions are precipitates of non-muscle myosin heavy-chain type IIA

IV.A.006

May-Hegglin disease. Blood film. Gray-blue giant neutrophil inclusion (arrow) and a giant platelet, the size of a red cell. Patients have a mutation of the MYH9 gene at chromosome region 22q12-13. The mutation results in disordered production of non-muscle myosin heavy-chain type IIA. This leads to macrothrombocytopenia, secondary to defective megakaryocyte maturation and fragmentation. Thrombocytopenia occurs in almost all patients, but severe bleeding is unusual. Individuals may bruise easily, and they may have recurrent epistaxis, gingival bleeding, menorrhagia, or excessive bleeding associated with surgical procedures. The neutrophil inclusions contain precipitates of non-muscle myosin heavy-chain type IIA.

IV.A.007

May-Hegglin disease. Blood film. Gray blue giant neutrophil inclusion (arrow) and giant platelets, the size of a red cell. Patients have a mutation of the MYH9 gene at chromosome region 22q12-13. The mutation results in disordered production of non-muscle myosin heavy-chain type IIA. This leads to macrothrombocytopenia, secondary to defective megakaryocyte maturation and fragmentation. Thrombocytopenia occurs in almost all patients, but severe bleeding is unusual. Individuals may bruise easily, and they may have recurrent epistaxis, gingival bleeding, menorrhagia, or excessive bleeding associated with surgical procedures. The neutrophil inclusions contain precipitates of non-muscle myosin heavy-chain type IIA.