Figure 1.

Pathological features of olfactory neuroblastoma. (A) The tumor cells were arranged in a lobulated or mass nest shape, surrounded by proliferative vascular fibrous stroma (hematoxylin and eosin, ×100); (B) the tumor cells were small, round, or short spindle shaped, with a deeply stained nucleus, a large nucleocytoplasmic ratio, obvious atypia, easy nuclear division, and a rich neurofibrillary tumor stroma (hematoxylin and eosin, ×400); (C) synaptophysin was diffusely positive in tumor cells (immunohistochemistry, ×200); (D) S100 was positive in Sertoli cells around the tumor cell nest (immunohistochemistry, ×200).