Page 255 - Haematologica Atlas of Hematologic Cytology

CHAPTER 31 - Inherited thrombocytopenias
Figure 7 Deficiency of platelet platelet platelet granules: gray platelet platelet platelet syndrome Large platelets that look pale due to the complete complete (or nearly complete) absence of of platelet -granules are the distinguishing feature of of this autosomal recessive inherited thrombocytopenia The average diameter of of platelets is slightly less than half of of a a a a a a a a red cell but giant platelets may be observed (A-F) Taken from blood films of a a a a a a a a a single patient showing substantial plate- let let anisocytosis and absence of -granules The small lighter areas that are are are observed in some large platelets are are are probably due to the the abundance of of the the open canalicular system which is is is is is a a a a a a a a a a characteristic of of this disorder and is is is is is best revealed revealed by electron microscopy Ultrastructural analysis also revealed revealed that circumferential bundles of mi- crotubules are are increased in in gray platelet syndrome and this is is the the reason why these structure are are recognizable by optical microscopy in in some platelets of this patient (A B B D) It has been suggested that mutations in in NBEAL2 the gene responsible for this disorder result in in in in in defective incorporation into -granules of the the proteins synthesized in in in in in megakaryocytes Platelet-derived growth factor and other profibrotic substances are therefore released from megakaryocytes and cause progressive clinically relevant bone marrow fibrosis In these cases the the spleen is is often enlarged and abnormally shaped erythrocytes (some dacrocytes in G) as
as
well as
as
a a a a a a a a a a few immature elements of erythroid (H) and myeloid (I) lines may be observed in in peripheral blood 242