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Okafor et al. Mini-invasive Surg 2024;8:28 https://dx.doi.org/10.20517/2574-1225.2023.128 Page 3 of 15

DIAGNOSTIC WORKUP
Upon initial presentation to an otolaryngologist, thorough physical examination serves as the critical first
step. Physical examination requires baseline, head and neck, neurologic and ophthalmologic examination as
well as nasal endoscopyIt is prudent to perform a detailed head and neck examination as rates of cervical
nodal metastasis at the time of diagnosis range from 5% to 8.7% of cases [6,25,26] . Furthermore, there are
significant outcome differences in treatment success for patients with nodal disease compared to those
[4]
without cervical metastasis which further highlights the significance of evaluating nodal involvement .
In addition to physical examination, imaging plays an essential role in the diagnosis, staging and
management of olfactory neuroblastoma. The first-line protocol for imaging consists of both CT and MRI
[27]
with and without contrast . CT is utilized to delineate possible osseous involvement of the cribriform
plate, orbit and sinuses while MRI will detail soft tissue involvement in the sinonasal cavities, orbit,
[28]
meninges, brain parenchyma and perineural invasion . Following initial diagnosis, these imaging studies
are needed to initiate preoperative planning and management and assess regional and distant disease. While
the cervical lymph nodes are the most common site of metastasis, additional sites include the breast, lung,
bone, prostate, abdomen, or central nervous system either by intracranial extension through the cribriform
plate or seeding of the cerebrospinal fluid (CSF) [29,30] .

The appearance of olfactory neuroblastoma on imaging is nonspecific and can be confused with other skull
base or intracranial masses such as meningiomas . However, notable features on imaging include a
[27]
dumbbell-shaped mass spanning across the cribriform, with CT illustrating a heterogeneous mass exhibiting
bony erosion notably at the cribriform, while MRI shows a T1 hypointense and T2 isointense mass, which
clearly distinguishes it from that of secretions [27,31] . With intracranial extension, peritumoral cysts at the
tumor brain interface are characteristic findings. [18F]-Fluorodeoxyglucose (FDG) PET may be used in
evaluation of advanced disease or to evaluate treatment response. Recently, the use of [68Ga]-DOTATATE
PET was found to be superior to FDG PET due to the tumor’s increased expression of somatostatin
receptors (SSTRs), which serve as a molecular target and are well-illustrated on whole-body [68Ga]-
DOTATATE PET scans [28,32,33] . Nonetheless, the anatomic extent of the tumor is critical to the staging of
these cancers, which impacts prognosis and survival outcomes.

HISTOPATHOLOGY
Following physical examination and review of imaging, diagnostic biopsy remains the gold standard for
definitive diagnosis. The biopsy can be performed in the office under local anesthesia or in the operating
room under general anesthesia. This decision depends on a patient’s bleeding risk and the tumor
characteristics.

Prior to determining whether an in-office or intraoperative biopsy can be performed, both the patient’s
bleeding risk and the tumor’s vascularity must be assessed. If a patient is on anticoagulation, the provider
must contact the patient’s cardiologist, hematologist or prescribing physician to establish appropriate timing
to hold and resume anticoagulation in the preoperative and postoperative setting . To assess tumor
[34]
vascularity, imaging modalities such as Doppler ultrasound, computed tomography angiography (CTA), or
magnetic resonance angiography (MRA), and fluorescence angiography are used to identify cerebral
vascular blood supply and its relationship to the tumor. Should the tumor be in the posterior sinonasal
space and or noted to be highly vascular on imaging, then biopsy should be performed in the operating
room.