Case Presentation - Fall, 2016

Olfactory Neuroblastoma Fall 2016

Written by: Alissa Ealy, student, Cleveland Clinic School of Cytotechnology, Cleveland, Ohio

Patient Information: 65-year-old male

Patient History: 65-year-old male presents with a right temporal mass. He is eleven years status post surgery, radiation and chemotherapy for olfactory neuroblastoma in the paranasal sinus with neck nodal involvement. He underwent an additional course of radiation for recurrence after one year. Subsequently he has had no evidence of disease.

Specimen type: Right temporal mass, fine needle aspirate, ThinPrep® non-Gyn-sample and Cellient® Cell Block

Case provided by: Department of Cytopathology, Cleveland Clinic, Cleveland, Ohio

Cytologic Diagnosis: Positive for malignant cells. Malignant cells present consistent with olfactory neuroblastoma (esthesioneuroblastoma). Comment: The current sample was compared with the patient’s prior resection for olfactory neuroblastoma and is morphologically similar.

Olfactory Neuroblastoma


Olfactory neuroblastoma (ONB) is a rare sinonasal tract malignancy thought to arise from neuroepithelial olfactory cells. Etiology is currently unknown. Olfactory neuroblastoma comprises only 2% of sinonasal tract tumors with an incidence of approximately 0.4 per million population. The tumor can occur at any age but usually has a bimodal distribution in the 2nd and 6th decades.

Clinical Features:
Symptoms can include unilateral nasal obstruction and epistaxis. Headaches, lacrimation and pain are reported less often. The most common imaging finding is a “dumbbell-shaped” mass that extends across the cribriform plate. Anosmia (loss of smell) is unusual.

Treatment and Prognosis:
Treatment consists of surgery and radiotherapy (with or without chemotherapy). Surgery often requires a bicranial-facial approach removing the cribriform plate. An endonasal approach may be feasible for some cases. The overall 5-year survival rate is 60-80%, depending on stage and grade. Recurrences develop in about 30% of patients, usually within the first two years of treatment. However, late recurrence is also common.

ONB has a “small, round, blue cell” presentation on cytology. FNA may show single cells with loose cohesion and scant cytoplasm. Cells are small with round, monomorphic nuclei and have fine, salt and pepper chromatin. Nucleoli are inconspicuous or small depending on grade. Immunohistochemistry is positive for chromogranin and synaptophysin.

Differential Diagnosis:
The differential diagnosis for sinonasal tract neoplasms is diverse and includes epithelial, lymphoid and mesenchymal tumors. A “dumbbell shaped” cribriform mass on imaging is a characteristic finding of olfactory neuroblastoma. ONB only occasionally has necrosis. In addition to staining positive for chromogranin and synaptophysin, ONB can stain focally or weakly positive for keratin and >90% stain positive for NSE. Sustentacular cells stain positive for S100. Described below are several other entities to consider in the differential diagnosis for “small, round, blue cell” tumors in the sinonasal tract.

Sinonasal undifferentiated carcinoma shows marked destruction on imaging. Cells are medium size with inconspicuous nucleoli. Necrosis is prominent. This tumor stains positive for keratin in >90% of cases, NSE in 50%, S100 and synaptophysin in <15%

Squamous cell carcinoma shows little destruction on imaging. Cells should have squamous differentiation. Necrosis may be limited. The tumor cells will stain positive for keratin while NSE, S100 and synaptophysin are negative.

Neuroendocrine carcinoma may invade the skull base or orbit on imaging. Cells have salt and pepper chromatin. Necrosis is prominent. Keratin, NSE, S100 and synaptophysin stains will be positive.

Ewing sarcoma/PNET can show bulky disease that may involve the maxilla on imaging. Cells are round and medium in size with fine chromatin and vacuolated cytoplasm. Necrosis is frequent. The tumor cells rarely stain positive for keratin and S100 but NSE and synaptophysin stain positive.

Rhabdomyosarcoma tumor size and extent is detected on imaging. The rhabdomyoblast cells are round, strap, or spindle shaped. Necrosis is limited. Keratin, NSE, S100 and synaptophysin stains are negative.

Extranodal NK/T cell lymphoma nasal type has non-specific findings early on imaging but later can show midline destruction. Cells are polymorphous with folds and cleaved nuclei. Necrosis is prominent. Keratin, NSE, S100 and synaptophysin stains are negative while EBER in situ hybridization is nearly 100% positive.

Melanoma in the sinonasal tract can show a central destructive mass on imaging. Cells are large, vary in shape and may be pigmented. Necrosis is limited. Melanoma will stain negative for keratin, NSE and synaptophysin and S100 positive.


  • Bibbo M, et al. Comprehensive Cytopathology. 4th ed. London, New York, Oxford, Philadelphia: Elsevier Saunders; 2015.

  • Banuchi VE, et al. Patterns of regional and distant metastasis in esthesioneuroblastoma. Laryngoscope. 2016;0:0-0. doi:10.1002/lary.25862.

  • Hafezi S, et al. Ewing’s Family of Tumors of the Sinonasal Tract and Maxillary Bone. Head Neck Pathol. 2011;5(1):8-16. doi:10.1007/s12105-010-0227-x.

  • Papacharalampous GX, et al. Olfactory neuroblastoma (esthesioneuroblastoma): towards minimally invasive surgery and multi-modality treatment strategies – an updated critical review of the current literature. JBUON. 2013;18(3):55-563.

  • Roxbury CR, et al. Endoscopic Management of Esthesioneuroblastoma. Otolaryngol Clin North Am. 2016;49(1):153-65. doi:10.1016/j.otc.2015.09.010.

  • Simons SA, et al. Sinonasal small round blue cell tumors: An approach to diagnosis. Semin Diag Pathol. 2016;33(2)91-103. doi:10.1053/j.semdp.2015.09.010.

  • Thompson LDR. Olfactory Neuroblastoma. Head Neck Pathol. 2009;3(3):252-259. doi:10.1007/s12105-009-0125-2.

  • Thompson LDR. Sinonasal Carcinomas. Curr Diagn Pathol. 2006;12(1)40-53. doi:10.1016/j.cdip.2005.10.009.