Microvessel density and Ki-67 labeling index in esthesioneuroblastoma: is there a prognostic role?

Esthesioneuroblastoma (ENB) is a malignant neuroectodermal tumor. Hyams grading has an established role in its prognostication. The importance of microvessel density (MVD) and Ki-67 labeling index (Ki-67 LI) is well studied in various tumors, but the same remains understated in ENB. The aims of the study were to estimate proliferation index and MVD in ENB and to correlate them with Hyams grade. Twenty-six ENB cases diagnosed over a period of 5 years were included. Hyams grade, MVD, and Ki-67 LI were evaluated for each of them. The cases were categorized as low (Hyams grades 1 and 2) and high (Hyams grades 3 and 4) grades. Microvessel density and Ki-67 LI were correlated with grade. The treatment response was analyzed in different grades. The commonest histologic grade was 4 (42%). The mean Ki-67 LI was 2%, 8.2%, 30.8%, and 40.5% and mean MVD was 81.67/mm(2), 37/mm(2), 24/mm(2), and 25.2/mm(2) in grades 1, 2, 3, and 4, respectively. A statistically significant correlation of grade with Ki-67 LI (P < .001) and MVD (P < .007) was noted. Hyams grade in ENB correlates well with treatment response. Ki-67 LI is an important prognostic factor in ENB. We propose a cutoff of 25% for Ki-67 LI to differentiate low- vs high-grade ENB, but larger studies are needed for validation. Contrary to epithelial tumors, there is a decrease in MVD with increasing grade in ENB.