Diagnosis
Esthesioneuroblastoma (Olfactory neuroblastoma)
Findings
A sagittal T1 image (Figure A) demonstrates a large, lobulated, soft-tissue mass filling
the superior aspect of the nasal cavity with extension into the anterior
cranial fossa. A post-contrast coronal T1 image (Figure B) demonstrates
moderately intense enhancement of the soft-tissue mass extending from the
sinonasal cavity into the anterior cranial fossa. The axial T2 image (Figure C)
reveals extensive surrounding vasogenic edema and mass effect upon the frontal
lobes and corpus callosum. A peripheral cyst is seen along the margin of the
intracranial mass (arrow). An axial-gradient echo image (Figure D) demonstrates
multiple regions of internal susceptibility corresponding to calcifications and
hemorrhagic foci.
Discussion
Olfactory neuroblastoma, also known as
esthesioneuroblastoma, is an uncommon tumor that arises from the basal neural
cell of the olfactory mucosa at the level of the cribriform plate. Therefore,
it typically presents as a superior nasal fossa tumor. Gross intracranial
spread occurs in approximately 30% of cases, but microscopic involvement of the
dura overlying the cribriform plate is the rule, as would be expected based on
the site of origin of the lesion.
Symptoms are quite nonspecific (patients have often had many months of nasal stuffiness, epistaxis, and headache), so these tumors are generally large at the time of presentation. The neoplasm has a bimodal
distribution of presentation in the 2nd and 6th decades.
Computed tomography (CT) will show a homogeneously enhancing mass centered in the superior nasal cavity/cribiform plate with bone destruction and speckled calcification.
Magnetic resonance imaging (MRI) demonstrates regions of hemorrhage, and generally intense and relatively homogeneous enhancement. Cystic areas at the margins of the intracranial tumor component have been described. It has been suggested that these cystic regions are a relatively specific sign
of esthesioneuroblastoma.
These tumors are generally treated with a combination of surgery (anterior skull base en bloc resection) and radiation therapy, with chemotherapy in some cases as well.
The reported 8-year, disease-free survival rate for esthesioneuroblastoma is approximately 80%, although
small tumors with limited intracranial extension have cure rates in the 85%- to 90%-range. Local recurrence rate is reported up to 57%. Cervical and retropharyngeal lymph nodes and distant metastases are relatively uncommon but important prognostically.
- Howell MC, Branstetter BF 4th, Snyderman CH. Patterns of regional spread for esthesioneuroblastoma. AJNR Am J Neuroradiol. 2011;32:929-933. Epub 2011 Feb 24.
- Yu T, Xu YK, Li L, et al. Esthesioneuroblastoma methods
of intracranial extension: CT and MR imaging findings. Neuroradiology. 2009;51:841-850. Epub 2009 Aug 11.