Olfactory neuroblastoma: a case report.

A neuroblastoma arising in the nasal cavity of a 66-year-old male invaded the frontal sinus and extended into the cranial cavity. Light microscopy revealed sheets of small ovoid cells and many small glands bordered by columnar cells which were strongly immunoreactive to epithelial markers. Focal reactivity for synaptophysin and chromogranin was seen within the sheets of small cells. Electron microscopy confirmed the presence of olfactory differentiation.