Argyrophilic nucleolar organizer regions (AgNOR) have been correlated with proliferative activity of neoplasms. Increased AgNOR may reflect increased proliferative activity of cells or ploidy. To explore this hypothesis, 41 breast carcinomas were processed for AgNOR silver staining and DNA flow cytometry. AgNOR counts were expressed as mean AgNOR/nucleus and percentage of tumor cells with more than five AgNOR/nucleus. The first count was designated mean AgNOR or mAgNOR, and the second count was designated AgNOR proliferative index or pAgNOR. Using Mantel‐Haensel statistical analysis, carcinomas that exhibited mAgNOR of 2.4 or more had a high likelihood of aneuploidy (P < 0.0001), an S‐phase fraction of more than 5.8% (P < 0.003), or a diameter greater than 2 cm (P < 0.007). In addition, tumors with pAgNOR of 8% or more showed a statistically significant correlation with aneuploidy (P < 0.004), tumor grade (P < 0.04), and a more significant one with high S‐phase fraction (P < 0.0001). No significant correlation was obtained between pAgNOR and tumor size or lymph node status. These data indicate that AgNOR quantitation reflects changes in DNA ploidy and cell proliferation. They also suggest that the mean AgNOR counts correlate best with the DNA mass or ploidy and that the frequency of cells with higher AgNOR count best reflects proliferative activity or S‐phase fraction.

Review of the literature reveals much disparity regarding the incidence, natural history, and survival rate in patients harboring esthesioneuroblastoma (olfactory neuroblastoma). The metastatic tendencies of this tumor have been highly variable in the literature, and reported intracranial involvement has been via local extension from the tumor's origin near the cribriform plate. Our present case describes a metastasis of esthesioneuroblastoma to the right parietal cortex and meninges in a patient without evidence of local recurrence after combined surgical and radiation therapy 5 years previously. The broad spectrum of biological behavior of this tumor, and its response to various therapies are discussed. The immunohistochemical and ultrastructural features of this unusual tumor are also presented. Recommendations are made for the management of these patients, including regular serial neurological examinations, serial computed axial tomography or magnetic resonance imaging of the head and neck, and, in the initial management, chemotherapy.