Diagnosis:
Dense Granule Contents
• Dense bodies are round, electron-opaque (dark) platelet organelles when visualized by electron microscopy.
• They have a distinct appearance on electron microscopy referred to as a bull’s-eye.
• Dense bodies contain adenosine diphosphate (ADP), adenosine triphosphate (ATP), serotonin, calcium, magnesium, and pyrophosphate.
• The other type of organelles found in platelets are the α-granules, which are less dense and more numerous by electron microscopy.
• α-Granules contain platelet derived growth factor (PDGF), β-thromboglobulin, factor V, P-selectin, fibrinogen, von Willebrand factor (vWF), platelet factor 4 (PF4), and other proteins.
• Absent or abnormal α- and dense granules can lead to abnormal platelet function, such as in gray platelet syndrome and Hermansky-Pudlak syndrome, respectively.
• It should be noted that connections between α-and dense granules may occur in the Golgi apparatus, in which case they may have shared contents.
