Nasal cavity, paranasal sinuses, nasopharynx

Other malignant tumors

Olfactory neuroblastoma

Editorial Board Member: Kelly Magliocca, D.D.S., M.P.H.
Editor-in-Chief: Debra L. Zynger, M.D.
Bin Xu, M.D., Ph.D.

Last author update: 29 September 2020
Last staff update: 18 August 2022

Copyright: 2004-2023,, Inc.

PubMed Search: Olfactory neuroblastoma

Bin Xu, M.D., Ph.D.
Page views in 2022: 22,006
Page views in 2023 to date: 20,136
Cite this page: Xu B. Olfactory neuroblastoma. website. Accessed September 25th, 2023.
Definition / general
  • Malignant neuroectodermal tumor commonly located at superior aspect of nasal cavity showing neuroblastic differentiation (El-Naggar: WHO Classification of Head and Neck Tumours, 4th Edition, 2017)
  • Thought to arise from olfactory membrane or olfactory placode (plate-like thickening of embryonic ectoderm from which a nerve ganglion or sensory organ will develop) which extends from roof of nasal cavity in fetus to midnasal septum and superior turbinate
  • Not related to neuroblastoma elsewhere in body
Essential features
  • Originated and centered around cribriform plate of nasal cavity
  • Small blue round cell tumor with lobulated growth pattern and abundant neuropil
  • Homer Wright pseudorosettes and Flexner-Wintersteiner rosettes may be seen
  • The most important prognostic factors are Hyams grade and Kadish stage
  • Also called esthesioneuroblastoma, esthesioneuroepithelioma or olfactory placode tumor
ICD coding
  • ICD-O: 9522/3 - Olfactory neuroblastoma
  • ICD-10: C30.0 - Malignant neoplasm of nasal cavity and middle ear
  • Usually confined to the cribriform plate and upper nasal vault; rarely in nasopharynx, maxillary or ethmoid sinus (Mod Pathol 2017;30:S1, Head Neck Pathol 2009;3:252)
  • May become locally invasive into paranasal sinuses, nasopharynx, palate, orbit, skull base, brain
  • Theorized to originate from specialized sensory neuroepithelium located in superior nasal cavity, including cribriform plate of ethmoid, nasal roof, superior nasal concha and superior nasal septum (Mod Pathol 2017;30:S1, Head Neck Pathol 2009;3:252)
  • None identified
Clinical features
  • Usually presents with nonspecific syndromes of nasal obstruction, epistaxis, headache and rhinorrhea (Mod Pathol 2017;30:S1, Head Neck Pathol 2009;3:252)
  • Rare symptoms include anosmia, visual disturbance, paraneoplastic syndromes (e.g. syndrome of inappropriate antidiuretic hormone secretion (SIADH))
Radiology description
  • Typical finding is a dumbbell shaped mass centered at cribriform plate
Radiology images

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Tumor extending into cribriform plate and lateral lamella

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Large, avidly enhancing skull base mass in left nasal cavity

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Olfactory neuroblastoma, a. coronal view, b sagittal view

Prognostic factors
Diagrams / tables
Table 1: Hyams grade for olfactory neuroblastoma
Grade I Grade II Grade III Grade IV
Architecture Lobular Lobular Variable Variable
Fibrillary matrix Prominent Present Minimal Absent
Mitosis Absent Present Prominent Marked
Necrosis Absent Absent May present Common
Nuclear pleomorphism Absent Moderate Prominent Marked
Rosettes Homer Wright Homer Wright Flexner-

Table 2: Staging systems of olfactory neuroblastoma
Kadish staging:  
  1. Confined to nasal cavity
  2. Involves nasal cavity and paranasal sinuses
  3. Extends beyond the nasal cavity and paranasal sinuses

Morita modification:  
  1. Confined to nasal cavity
  2. Involves nasal cavity and paranasal sinuses
  3. Extends beyond the nasal cavity and paranasal sinuses
  4. Regional or distant metastasis
Case reports
  • Complete surgical excision (may require craniofacial resection), with radiation therapy or chemotherapy
Clinical images

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Nasal endoscopy

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Bifrontal craniotomy

Gross description
  • Red-gray, highly vascular, polypoid mass
Microscopic (histologic) description
  • Low grade olfactory neuroblastoma usually contains nests and lobules of monotonous tumor cells with round nuclei, indistinct nucleoli and scanty cytoplasm in association with a vascular-rich to hyalinized stroma; fibrillary neural matrix may be present
  • High grade tumors may show solid growth, marked mitotic activity, nuclear pleomorphism, necrosis and no neuropil
  • Homer Wright pseudorosettes: neoplastic cells palisading around a central zone of fibrillar neural matrix; their presence in a nasal tumor is characteristic for olfactory neuroblastoma
  • Flexner-Wintersteiner rosettes: palisading tumor cells surrounding a true central lumen
  • Perivascular pseudorosettes may be present but are non-specific
  • Other findings: melanin pigment, neurons, divergent differentiation (e.g. rhabdomyoblastic, glandular and squamous differentiation)
Microscopic (histologic) images

Contributed by Bin Xu, M.D., Ph.D.
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Lobulated growth,
abundant fibrillar
neural matrix

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Lobulated growth with
infiltration between
submucosal glands

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Hyams grade I

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Homer Wright

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diffusely positive
in tumor cells

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S100 highlights
sustentacular cells

Positive stains
Negative stains
Electron microscopy description
Molecular / cytogenetics description
  • Recent next generation sequencing studies have shown that olfactory neuroblastoma has high level but heterogenous chromosomal instability and copy number alterations (Oncotarget 2016;7:52584)
  • Absence of characteristic fusions of other small blue round cell tumors that may occur in the sinonasal tract, e.g. Ewing sarcoma EWSR1 fusion and alveolar rhabdomyosarcoma PAX3 or PAX7 fusion
Sample pathology report
  • Nasal cavity, left; biopsy:
    • Olfactory neuroblastoma, Hyams grade II (see comment)
    • Comment: Immunohistochemistry studies show that the tumor is positive for synaptophysin and chromogranin, whereas negative for cytokeratin. S100 highlighted the sustentacular network. The overall immunoprofile supports the diagnosis.
Differential diagnosis
Board review style question #1
    A biopsy of a sinonasal mass from a 50 year old man is shown here:

    Which of the following statements is true?

  1. The tumor most commonly locates to the lower portion of nasal cavity
  2. Tumor necrosis, nuclear pleomorphism and high mitotic index are part of the staging system
  3. The tumor is not associated with similar appearing tumors elsewhere in the body
  4. SMARCB1 (INI1) immunohistochemistry is lost in this tumor
Board review style answer #1
C. Olfactory neuroblastoma is not associated with neuroblastoma elsewhere in the body

Comment Here

Reference: Olfactory neuroblastoma
Board review style question #2
    Which statement about olfactory neuroblastoma is true?

  1. The most important prognostic factor is N-MYC amplification
  2. It is most commonly originated from the medial wall of maxillary sinus
  3. Most tumors are diffusely positive for CAM5.2
  4. It may contain areas with rhabdomyoblastic differentiation
Board review style answer #2
D. It may contain areas with rhabdomyoblastic differentiation

Comment Here

Reference: Olfactory neuroblastoma
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