Olfactory neuroblastoma: A clinicopathological experience of a rare entity from Pakistan

Objectives: to present the clinicopathological experience of olfactory neuroblastoma (onb) with emphasis on histopathological and immunohistochemical features. methods: a descriptive cross-sectional study was done on 36 cases of onb,selected by non-probability purposive sampling. theses cases of onb were retrieved and reviewed from surgical pathology database of aga khan university hospital reported between january 1993 and march 2015. results: tumor size and age of presentation was wide in range without any distinct bimodal distribution. nasal cavity was most common site along with involvement of paranasal sinuses. more than 50% cases had kadish stage a. microscopically,most cases were grade-1 and majority showed partial or complete lobular architecture. neurofibrillary matrix was observed in 2/3rd of cases. among immunohistochemical markers,neuron specific enolase was most frequently expressed. unusual positive expression of cytokeratin ae1/ ae3 and cytokeratin cam5.2 was also seen focally in few cases. conclusion: the onb has great variability of histological and clinical presentation,and immunohistochemical markers are useful to differentiate from more common small round blue cell tumours of nasal cavity. © 2016,professional medical publications. all rights reserved.