Hematoxylin and eosin staining of a sagittal section of the resected mass. A; Fibrous tissue with hyaline degeneration surrounded the cavity where HA existed. (magnification, ×25; scale bar, 500 μm). B; A higher magnification of the boxed area in Figure A. In some parts of the marginal layer of the cavity, multinuclear giant cells and lymphocytes were observed, partially forming a foreign body granuloma (magnification, ×200; scale bar, 100 μm). C; A higher magnification of the boxed area in Figure A. Scant new bone formation is found in the HA cavity, or juxtaposed with fibrous tissue. Some new bone was necrotic. Black arrows indicate necrotic bone without osteocytes (magnification, ×100; scale bar, 200 μm). D; Further observation of new bone formation juxtaposed with fibrous tissue. Osteocytes were present in the new bone, but bone marrow formation was not observed (magnification, ×100; scale bar, 200 μm). 'B', New bone.