A clinicopathological Study of Olfactory Neuroblastoma

Purpose To analyze the clinical and pathological features, diagnosis and differential diagnosis of Olfactory Neuroblastoma, and enhance the accuracy of pathological diagnosis of the disease. Methods The clinical presentation, histological observation and immunohistochemical staining were analyzed in 13 cases of ONB and related literatures were reviewed. Results Their ages ranged from 17 to 59 years old, including 10 male and 3 female patients. Histologically, the tumor is composed of cells which have the same size and scant cytoplasm arranged in lobules and nests. The tumor cells are poorly delineated and have small round nuclei with salt-and pepper chromatin. Homer-Wright and Flexner-Wintersteiner rosettes can be found in some case. Immunohistochemically, the cells were typically positive for Syn, CD56, CgA, S-100, and Ki-67-labeling indices ranged from 15 to 80%. The results of follow-up of 4-72 months for 6 patients revealed that 5 patients recurred, including two metastasis. Conclusions ONB is a rare malignant tumor with aggressiveness. Its definite diagnosis comes from unique morphology, immunohistochemical expression and additional gene analysis.