Fig. 4

Histological examination and scanning electron microscope (SEM) image/energy-dispersive X-ray spectroscopy (EDS) microanalysis of the calcium pyrophosphate crystal. a Rod- and rhomboid-shaped crystal deposits were observed via hematoxylin and eosin staining (red arrow). b The crystal deposit is shown to have birefringence under polarized light (original magnification × 100). c SEM/EDS spectrum of the CPPD crystal