Fig. 3

Microscopic findings of the axillary lymph node. a Metastatic tumor cells contained mucin as indicated by D-PAS staining; however, mucin retention in the stroma was not observed. b The tumor cells were also found positive for mucin by alcian blue staining. c Necrosis was observed in the central region of the node, and the metastasized tumor cells were directly adjacent. d In the peripheral region of the lymph node, four small ossified lesions were found, and the metastasized tumor cells were directly adjacent to ossified nests (arrow) (× 40). e Osteocytes were observed inside the osseous matrix; however, osteoblast-like cells were not found around the HO lesion (× 100). The upper right is a magnified view of the tumor cells beside the HO lesion