Fig. 2

Morphological characterization of synovial MGC subtypes in OA and in RA. Foreign body giant cells were identified as MGCs with many nuclei diffusely distributed throughout the cytoplasm (a). Langhans giant cells were recognized by the multiple nuclei arranged in a horseshoe shape (b). Foam MGC subtype was characterized by numerous nuclei clustered together, surrounded by a foamy cytoplasm (c). Plasma MGC subtype was assessed by their eccentric nuclei with a dense distribution of chromatin (d). Overall MGC subtypes were identified in either OA or RA. Arrows indicate each different MGC subtype in synovium. Haematoxylin and eosin staining. Scale bars = 20 μm