Updated: Jun 04, 2021
Author: Michael Somenek, MD; Chief Editor: Herbert H Engelhard, III, MD, PhD, FACS, FAANS 


Practice Essentials

Esthesioneuroblastoma (ENB), also known as olfactory neuroblastoma, is a rare neoplasm originating from olfactory neuroepithelium. Due to the rare and complex nature of ENB, multiple opinions exist regarding the etiology, optimal staging system, and treatment modalities. These tumors often display varying biologic activity ranging from indolent growth, with patient survival exceeding 20 years, to a highly aggressive neoplasm capable of rapid widespread metastasis, with survival limited to a few months.

Images of esthesioneuroblastomas are shown below.

Esthesioneuroblastoma. Coronal CT scan of the orbi Esthesioneuroblastoma. Coronal CT scan of the orbits and sinuses shows a large, enhancing, and expansile mass occupying the ethmoid air cells that is invading the cribriform plate and breaking through to the left anterior cranial fossa. Image courtesy of Michael Lev, MD.
Esthesioneuroblastoma. A 39-year-old man presented Esthesioneuroblastoma. A 39-year-old man presented with 1 month of decreased vision, left facial numbness, and swelling. Physical examination demonstrated left-sided exophthalmos and blindness. He had also lost his sense of smell. Contrast-enhanced T1-weighted MRI demonstrated a large lesion that originated in the paranasal sinuses and extended through the cribriform plate into the anterior cranial fossa. He underwent a bifrontal craniotomy for resection of this tumor.

The prognosis depends on the magnitude of the disease on initial diagnosis. It should be noted that precise histologic diagnosis is difficult because ENBs are often confused with other small round cell neoplasms of the nasal cavity. Despite the difficulties associated with the treatment of ENB, evolving treatment modalities, including surgery, radiation, and adjuvant chemotherapy, have contributed to better management of ENB and increased survival of these patients.[1] See Treatment and Medication.


Esthesioneuroblastomas (ENBs) are undifferentiated tumors of neuroectodermal origin derived from the olfactory epithelium.[2] The tumor cells are mitotically active and are the precursor cells that develop into sustentacular and neuronal cells. Inconsistent histologic presentations initially led to controversy surrounding the exact histologic origin of ENBs, and this ambiguity can confound clinical and prognostic decisions. In essence, ENBs contain variable arrangements of their small cells. Additionally, there exists a variable presence (or absence) of true rosettes and neurofibrillary material.

To date, no certain genetic factor has been identified that can accurately assist in the diagnosis or predict prognosis. This is partially due to the ability to analyze cancer genomes on a whole genome basis. Recently, a tool called array comparative genomic hybridization was applied to the analysis of ENBs.[3] Although many alterations were identified in this study, chromosomal gains in 7q11 and 20q and deletions in 2q, 5q, 6p, 6q, and 18q have been confirmed by at least 2 other studies. Interestingly, 20q is a region that has been implicated in other cancers, including breast, ovarian, and squamous cell carcinoma. Still, further experimentation will be required to determine the role of these genomic regions in ENB.

The demonstration of human achaete-scute homologue (HASH1) gene expression, although still investigational, could become the diagnostic procedure of choice.[4] The HASH1 gene is involved in olfactory neuronal differentiation and is expressed in immature olfactory cells[5] ; therefore, it could be useful in distinguishing ENB from other poorly differentiated small blue cell tumors.



United States

Interestingly, 80% of the esthesioneuroblastoma (ENB) cases published in the literature since Berger and Luc described the first case in 1924 have been identified in the last few decades.[6] However, the current data set cannot distinguish between a rising incidence and better recognition of the disease. 

ENB has an estimated incidence of 4 cases per 10 million individuals and accounts for approximately 5% of all sinonasal tumors.  A search of the National Cancer Database by Carey et al identified 1225 cases of ENB.[7]  Similar incidence rates have been obtained through epidemiologic studies performed in Denmark.[8] No studies suggest a geographic variation in rates.

Race-, Sex-, and Age-related Demographics

ENB does not show a predilection toward any individual race. ENB does not show familial prevalence and has been reported in all races and on all continents. ENB affects males and females with similar frequency.

ENB occurs in a wide range of age groups (3-90 y). It has a bimodal peak of occurrence in the third and sixth decades of life.




The symptoms of esthesioneuroblastoma (ENB) can be classified into nasal, neurologic, oral, facial, cervical, and ophthalmologic and are as follows:

  • Nasal - Obstruction (70%), epistaxis (46%), discharge, unilateral polyp, anosmia

  • Neurologic - Headache, nausea

  • Oral (rare) - Mobile tooth, nonhealing tooth-extraction site, ill-fitting dental prostheses, ulceration

  • Facial (rare) - Swelling, pain, anesthesia, trismus

  • Cervical - Mass

  • Ophthalmologic - proptosis, extraocular movement paralysis, and blindness,

The average delay between the appearance of the initial symptom and the diagnosis is 6 months, but diagnosis is delayed for years in some cases. Delay is understandable because initial symptoms tend to be subtle and are frequently banal, occurring also in common nasal diseases, including long-term rhinosinusitis or allergic polypoid sinus disease.[9]

Many patients undergo sinus surgery, only to have the diagnosis established as an unexpected pathologic finding. Therefore, sending all the tissue removed during sinus surgery for pathologic examination is important for diagnosis of esthesioneuroblastoma, as is the vigilance of the pathologist in examining the tissue.

For the most part, malignancy is not considered until secondary symptoms such as facial pain and deformity or cranial nerve impairment are observed. However, early referral for an intranasal biopsy is essential to early diagnosis.[10] A patient with a unilateral nasal obstruction and/or recurrent epistaxis lasting longer than 1-2 months should undergo a thorough nasal evaluation by an otolaryngologist, although the cost-effectiveness of this approach has not been evaluated.


Nasal examination, particularly if aided by endoscopy, reveals a reddish-gray tumor arising in the upper nasal fossa, which bleeds easily with instrumentation. Although this aspect is strictly different from the white, glistening appearance of benign nasal polyps, little differentiates esthesioneuroblastoma (ENB) from other nasal malignancies. Late findings may include signs related to extensive disease such as orbital, cranial, and cervical involvement.


No clear etiologic agent or exposure has been documented in humans; however, a single case of occupational exposure has been reported in a woodworker.[11] Esthesioneuroblastoma (ENB) can be consistently induced by nitrosamine compounds in rodents. In cats with spontaneous ENB or in transgenic mice developing ENB, type C retroviral particles have been demonstrated and classified as feline and murine leukemia virus, respectively. The role of retrovirus sequences in human ENB remains to be evaluated.



Diagnostic Considerations

Other problems to be considered in the differential diagnosis of esthesioneuroblastoma include the following:

  • Nasal and paranasal squamous cell carcinoma

  • Sinonasal polyposis

  • Choanal polyp

  • Juvenile angiofibroma

  • Neuroendocrine carcinoma

  • Embryonal rhabdomyosarcoma

  • Undifferentiated sinonasal carcinoma

  • Ewing sarcoma

Differential Diagnoses



Laboratory Studies

No specific lab studies confirm the diagnosis of esthesioneuroblastoma (ENB). Because surgery often is contemplated and because open nasal procedures are associated with significant bleeding and may involve blood transfusions, a complete blood count may be obtained, and the patient should be advised about preoperative blood donation.

Imaging Studies

Computed Tomography

Standard radiographs do not have a role in the evaluation of esthesioneuroblastoma (ENB). A direct coronal fine-cut (3 mm) computed tomography (CT)  scan is the initial radiologic study of choice.

ENB lacks a specific radiologic appearance and is seen as a homogeneous soft tissue mass with uniform and moderate contrast enhancement, as depicted in the image below.

Esthesioneuroblastoma. Coronal CT scan of the orbi Esthesioneuroblastoma. Coronal CT scan of the orbits and sinuses shows a large, enhancing, and expansile mass occupying the ethmoid air cells that is invading the cribriform plate and breaking through to the left anterior cranial fossa. Image courtesy of Michael Lev, MD.

Estthesioneuroblastoma that is isolated to the intranasal cavity can be indistinguishable from benign processes. A review of eight cases of intranasal esthesioneuroblastoma by Peckham et al identified the following three main CT findings[12] : 

  • An intranasal polypoid lesion with its epicenter in a unilateral olfactory recess
  • Asymmetric widening of the involved olfactory recess
  • Extension to the cribriform plate

CT images are essential for correct staging and should be evaluated carefully for erosion of the lamina papyracea, cribriform plate, and fovea ethmoidalis specifically.

Obstruction of the sinus-draining ostia results in an accumulation of nasal secretions, which tend to be difficult to differentiate from tumor tissue when viewed on CT scan.

An unusual but characteristic imaging feature of ENBs is the presence of cysts at the tumor-brain interface.[13]

Magnetic Resonance Imaging

MRI often is necessary to better delineate sinonasal and intraorbital extension or an intracerebral extension.

Using MRI, ENB appears as hypointense to gray matter on T1-weighted images and isointense or hyperintense to gray matter on T2-weighted images, as depicted in the second image above.

Because details of bony erosion are better demonstrated by CT images, both studies usually are required in the majority of patients.

An example image is shown below.

Esthesioneuroblastoma. A 39-year-old man presented Esthesioneuroblastoma. A 39-year-old man presented with 1 month of decreased vision, left facial numbness, and swelling. Physical examination demonstrated left-sided exophthalmos and blindness. He had also lost his sense of smell. Contrast-enhanced T1-weighted MRI demonstrated a large lesion that originated in the paranasal sinuses and extended through the cribriform plate into the anterior cranial fossa. He underwent a bifrontal craniotomy for resection of this tumor.


Since most ENBs express somatostatin receptors, the use of scintigraphy with a radiolabeled somatostatin analog (111 In-pentoctreotide [111 In-DTPA-D-pheoctreotide]; Octreoscan) has been proposed. A preliminary study of this technique found it to be clinically useful, especially for discriminating between postoperative changes and residual or recurrent tumor after extensive skull base surgery.[14] The sensitivity and specificity remain unclear, however.

Histologic Findings

Esthesioneuroblastomas (ENBs) can display various histologic presentations. The hallmark of well-differentiated ENBs is arrangements of cells into rosettes or pseudorosettes (sheets and clusters). True rosettes (Flexner-Wintersteiner rosettes) refer to a ring of columnar cells circumscribing a central oval-to-round space, which appears clear on traditional pathologic sections. Pseudorosettes (Homer-Wright rosettes) are characterized by a looser arrangement and the presence of fibrillary material within the lumen.

One common method of stratification is to separate ENBs into 2 distinct groups: neuroblastomas proper and neuroendocrine carcinomas. The first group, neuroblastomas proper, has a histologic presentation similar to that of peripheral neuroblastomas of childhood. This group of ENBs is composed of sheets of poorly demarcated groups of cells separated by fine connective tissue trabeculae. The cells are small and typically show no mitotic activity. Importantly, these masses contain fibrillary material between the cells. Rosettes of the Homer-Wright type are present. One observed feature on electron microscopy is the presence of a dendritic cytoplasmic process with accumulations of small dense core granules within the process.[15]

The unique feature of neuroendocrine carcinomas, the second class of ENBs, is admixture with glands. A neurofibrillary component is absent, and the growth pattern is that of solid nests without rosettes. In some cases, ENBs present as neoplastic cells that are intimately related to the basal epithelium of the glands, and a neurofibrillary component is not seen. The cells in these tumors are typically larger than those in neuroblastomas, and the growth pattern is that of solid nests without rosettes. Dense core granules similar to those of neuroblastoma are present in the cytoplasm and cytoplasmic extensions.

Further confounding accurate diagnosis is the fact that ENB is histologically similar to other small, round blue cell tumors. The acronym LEMONS ( lymphoma, Ewing sarcoma, melanoma, olfactory/ other [ENBs, rhabdomyosarcoma or Markel cell carcinoma], neuroblastoma, and small cell carcinoma) defines the other tumors from which ENB should be differentiated. Distinguishing ENBs from the other tumors is of paramount importance because the tumors respond differently to various treatment modalities.

The following list describes the outcome of each of these diseases with various immunohistochemical tests.

  • Esthesioneuroblastomas stain positive for S-100 protein and/or neuron-specific enolase, while the stain usually is negative for cytokeratin, desmin, vimentin, actin, glial fibrillary acidic protein, UMB 45, and the common leukocytic antigen. For difficult cases, electron microscopy can be useful. Common features are small, round neuroepithelial cells arranged in rosette or pseudorosette patterns, separated by fibrous elements. Rosettes consist of a central space ringed by columnar cells with radially oriented nuclei.

  • Lymphoma can be excluded when the majority of tumor cells are negative for CD45 (the remaining positive cells demonstrate no atypical immunophenotype).

  • Ewing sarcoma is positive for MIC2/CD99 gene products that result from an 11;22 translocation.[16]

  • Melanoma can be identified using a combination of immunohistochemical markers: MART-1/Melan-A, HMB-45, and S-100. S-100 is expressed in more than 95% of melanomas.

  • Rhabdomyosarcoma displays a loss of chromosome 11 and stains positive for desmin (expressed in 95%), muscle-specific actin, and myoglobin.

  • Markel cell carcinoma stains positively for low-molecular-weight cytokeratin 20 and NSE.

  • Neuroblastoma often stains positive for NSE, synaptophysin, Leu7, and neurofilament protein. Elevated serum catecholamines are also suggestive of neuroblastoma.

  • Small cell carcinomas stain positively for chromogranin, NSE, and synaptophysin (presynaptic nerve cell vesicles). Most small cell carcinomas are positive for TTF-1.

In summary, the pathologic distinction of poorly differentiated small neoplasms of the nasal cavity is difficult and is based on a panel of immunohistochemical stains and, if necessary, electron microscopy. To date, no specific immunocytologic stain identifies ENB; however, knowledge of the histochemistry of other related tumors can distinguish them. When ENB is suspected, diagnostic tests should include S-100 protein, neuron-specific enolase, chromogranin and/or synaptophysin, cytokeratin, desmin, actin, UMB 45, common leukocytic antigen, and myc-2 protein.

ENB can be graded histologically by the Hyams system, which is based on the preservation of lobular architecture, mitotic index, nuclear polymorphism, and the presence of fibrillary matrix, rosettes, and necrosis.[17] The Hyams system is based on 4 grades, which are described in Table 1, below.

Table. Histopathologic Grading According to Hyams [17] (Open Table in a new window)


Lobular Architecture Preservation

Mitotic Index

Nuclear Polymorphism

Fibrillary Matrix








HW rosettes







HW rosettes







FW rosettes










Tumor staging is an important guide for prognosis and therapy. Several staging systems, including Hymans (see Pathophysiology, above), Kadish, and tumor-node-metastasis (TNM) systems, have been proposed as a guide to choosing treatment modalities.

From a limited series of 17 patients, Kadish et al were the first to propose a staging classification for esthesioneuroblastoma (ENB).[18] ENBs were divided into the following 3 categories:

  • Group A – Tumors limited to the nasal fossa
  • Group B – Tumors with extension to the paranasal sinuses
  • Group C – Tumors with extension beyond the paranasal sinuses and nasal cavity

Some authors have noted that effectively stratifying patients with the Kadish system can be difficult. Recognizing these inadequacies, Morita et al in 1993 published a revised Kadish system that redefined stage C (consisting of local disease spreading beyond the paranasal sinuses) and included a stage D (distant metastasis).[19]

In 1992, Dulguerov and Calceterra proposed a classification based on the TNM system, which is predicated on CT and MRI findings that can be identified before treatment.[20] Although this classification system has gained popularity, attempts have been made to further modify the Kadish system for ENB.

The TNM classification is as follows:

  • T1 - Tumor involving the nasal cavity and/or paranasal sinuses (excluding sphenoid), sparing the most superior ethmoidal cells
  • T2 - Tumor involving the nasal cavity and/or paranasal sinuses (including the sphenoid), with extension to or erosion of the cribriform plate
  • T3 - Tumor extending into the orbit or protruding into the anterior cranial fossa, without dural invasion.
  • T4 - Tumor involving the brain
  • N0 - No cervical lymph node metastasis
  • N1 - Any form of cervical lymph node metastasis
  • M0 - No metastasis
  • M1 - Distant metastases present

A TNM-based staging system proposed by Sun et al[21] divides the T component into the following four categories:

  • T1 - Tumor limited to the nasal cavity and/or ethmoid sinus (excluding the cribriform plate)
  • T2 - Tumor involving the nasal cavity and/or paranasal sinuses with extension to or erosion of the cribriform plate, pterygoid process and/or lamina papyracea
  • T3 - Tumor extending to invade the orbit, anterior orbital contents, hard palate, nasopharynx, or clivus
  • T4 - Local advanced disease with invasion of any of the following: orbital apex, dura, brain, or cranial nerves.

The N component is divided into the following three categories:

  • N0 - No regional lymph node metastasis
  • N1 - Metastasis in unilateral or bilateral lymph nodes, ≤6 cm in greatest dimension, above the supraclavicular fossa
  • N2 - Lymph node metastasis > 6 cm in dimension or extension to the supraclavicular fossa

Staging is shown in the table below.

Table. Stage Grouping for Esthesioneuroblastoma (Open Table in a new window)
































The 5-year overall survival in this system by stage is as follows[21] :

  • Stage I - 100%
  • Stage II - 89%
  • Stage IIIA - 78%
  • Stage IIIB - 60%
  • Stage IVA - 0%
  • Stage IVB - 0%


Grossly, esthesioneuroblastoma (ENB) appears as a gray to red mass in the nasal vault. The color usually is related to the extent of tumor vascularization, raising the possibility of profuse nasal bleeding following the biopsy procedure.

Taking a biopsy specimen should be deferred until completion of the radiologic studies to avoid swelling effects on accurate imaging and the inadvertent biopsy of other nasal tumors of neurogenic origin.

Biopsy and endoscopy should be performed under general anesthesia. The specimen should be sent for regular staining, as well as for immunohistochemistry and possibly electron microscopy.



Approach Considerations

Due to the rarity and complexity of esthesioneuroblastoma (ENB), there exists considerable heterogeneity in treatment. Complete surgical resection of the tumor followed by radiation therapy is recognized by most studies as the optimal treatment.[1, 22, 23]  However, some institutions report success with alternative treatment sequences, including surgery without radiation. More recently, chemotherapy has been introduced in the therapeutic armamentarium. Because of the lack of any randomized trial comparing these treatment protocols, the available data are summarized below.

Single-modality therapy versus combined treatment

The literature gives little support to single-modality treatments; few studies advocate either surgery or radiation alone. A meta-analysis by Dulguerov et al clearly showed lower recurrence rates for the combination of surgery and radiotherapy.[24]

Some institutions advocate surgery alone for Kadish stage A tumors, whereas most suggest adjuvant radiotherapy for these lesions. A review by Carey et al found no difference in survival between surgery and surgery followed by radiation in patients with Kadish stages A and B tumors.[7]  A few studies advocate neoadjuvant chemotherapy for Kadish C lesions.

Unlike most surgical specimens from the head and neck, specimens from the nasal cavity and paranasal sinuses, even en bloc, are difficult to orient, and surgical margins are difficult to analyze. Because one can rarely be completely confident of the adequacy of surgical margins, postoperative radiation to minimize the risk of local recurrence seems justified in almost all patients.

Timing of surgery and radiation in combined therapy

Most institutions favor surgery as the first treatment modality, followed by postoperative irradiation.

Preoperative radiation results in the usual loss of definable tumor borders, which makes an en-bloc resection problematic. A theoretical advantage of preoperative radiation therapy is that it can convert an inoperable tumor to one that is amenable to resection, but that view is not widely supported.

Radiation technique

Standard techniques include external megavoltage beam and a 3-field technique; an anterior port is combined with wedged lateral fields to provide a homogeneous dose distribution. In current practice, the radiation portals are planned by integrating pretreatment CT or MRI imaging within the radiotherapy software.

The dose varies from 5500-6500cGy. The majority of patients receive < 6000 cGy. These doses are close to or exceed the maximum radiation dose recommended for sensitive structures such as the optic nerve, optic chiasma, brainstem, retina, and lens. Therefore, those patients are susceptible to cataract formation and glaucoma.

A possible role of proton beam radiotherapy, intensity-modulated radiotherapy, and stereotactic radiation has been suggested.[25, 26]  Several institutions have reported that intensity-modulated radiotherapy can provide good tumor control with low rates of radiation-induced toxicity, in children as well as in adults.[27, 28]

Case reports describe the use of CT-guided interstitial high-dose-rate brachytherapy.[29]  However, prospective clinical trials confirming the efficacy of these modalities have not yet been completed.

Role of chemotherapy

Chemotherapy is not recommended for routine treatment of ENB. Exceptions include palliative treatments or as part of a multimodality treatment in patients with advanced or metastatic disease.[30]

The use of chemotherapy has been advocated by authors from the University of Virginia.[31]  In their protocol, patients with advanced disease (eg, Kadish stage C) are treated first with 2 cycles of cyclophosphamide (300-650 mg/m2) and vincristine (1-2 mg) with or without doxorubicin, followed by 50 Gy of radiotherapy, which then is followed by a craniofacial resection. With this regimen, the 5-year and 10-year actuarial survival rates are 72% and 60%, respectively. Similar results have been obtained without chemotherapy, and how much chemotherapy contributed to the cure rates is unclear.

Cisplatin-based regimens are preferred at the Mayo Clinic[32, 33]  and at the Gustave-Roussy Institute in France,[34]  but even if ENBs are responsive to cisplatin, chemotherapy for high-grade tumors in the advanced setting is not curative.

At Harvard, the selected regimen is cisplatin (33 mg/m2/d) and etoposide (100 mg/m2/d) for 3 days. This has been followed by proton radiation in 9 patients, with excellent results.[25]  This is probably the only study that demonstrates convincingly the possibility of a nonsurgical treatment of ENB, although the patient population is small.

A more aggressive chemotherapy regimen was reported by Mishima et al.[35]  In 8 of 12 patients receiving a combination of cyclophosphamide, doxorubicin, vincristine, and continuous-infusion cisplatin and etoposide followed by radiation, a complete response was achieved. Toxicity was acceptable, according to the authors. Turano et al achieved success in treating advanced anult tumors by alternating cisplatin and etoposide with doxorubicin, ifosafimide, and vincristine.[36]

Biologic therapy

Case reports describe successful use of targeted biologic therapy in patients with progressive or recurrent ENB. Agents used have included tyrosine kinase inhibitors (TKIs), mammalian target of rapamycin (mTOR) inhibitors, and epidermal growth factor receptor (EGFR) inhibitors. For example, Spengler et al report a durable major response to treatment with the TKI pazopanib in a patient with recurrent, heavily pretreated metastatic ENB; pazopanib was selected after next-generation sequencing of the tumor demonstrated a presumably pathogenic mutation in the FH (fumarate hydratase) gene.[37]

Surgical Care

Surgery remains the primary treatment for esthesioneuroblastoma (ENB) and offers the best chance for locoregional control as well as survival. Both open and endoscopic craniofacial resection have achieved complete surgical resection with tumor-free margins. In the last 20 years, craniofacial resection followed by radiation therapy has been repeatedly referred to as the “gold standard” for treatment, and thus, other treatment modalities should be measured against it.

Open craniofacial resection permits en-bloc resection of the tumor, with assessment of any intracranial extension and protection of the brain and optic nerves. Features are as follows:

  • The en-bloc resection should include the entire ipsilateral cribriform plate and crista-galli.

  • The olfactory bulb and overlaying dura should be removed with the specimen.

  • Preservation of the contralateral olfactory system, when possible, results in a preserved sense of smell in a few cases.

  • A tumor that does not penetrate the orbit can be encompassed by resecting the lamina papyracea or even small segments of orbital periosteum.

  • To avoid late frontal sinus mucocele formation, the posterior table of the frontal sinus should be taken down, the mucosa removed, and the cranial contents allowed to fill the defect.

  • Repair of the dura is facilitated by the added exposure afforded by craniotomy. Although cranial floor defects as large as 4 cm may be present, bone grafts have not been necessary. The cranial floor is repaired by various techniques, including a pericranium flap, temporalis muscle and fascia transposition, or a layer of fascia lata held with thrombin glue. This prevents the herniation of cranial contents into the nasal cavity and the occurrence of cerebrospinal fluid leaks.

  • Pneumocephalus has been prevented in the immediate postoperative period by the placement of a nasal trumpet in the operated nasal fossa, along with necessary packing, to vent any coughed or pressurized air away from the cranial cavity.

  • Postoperative complications have been reported in 15-40% of cases. Major complications include (but are not limited to) frontal lobe abscess, infection, and intercranial hemorrhage.

Endoscopic craniofacial resection (ECFR)

ECFR has become a widely accepted treatment modality. Multiple studies have shown it to be a safe, feasible, and oncologically sound technique.[38, 39, 40, 23]  Initially, an endoscopic approach was limited to Kadish stages A and B; however, successful resections have been performed on stage C tumors.[38, 41]

The benefits of an endoscopic approach include decreased time in surgery, blood loss, morbidity, postoperative complications, and cost. However, excess bleeding can hinder the endoscopic approach. Endoscopic resection followed by gamma-knife stereotactic radiosurgery has demonstrated positive outcomes.

Key features unique to the endoscopic approach include the following:

  • Creating generous sphenoidotomies and drilling off the sphenoid rostrum to make a common sphenoid sinus cavity allowing exposure to the planum sphenoidale.

  • A Draf type III, Lothrop-type, frontal sinusotomy communicating both frontal sinuses across the midline to expose a common frontal sinus cavity.

  • Using a high-speed cutting bur, performing an anterior fossa craniotomy bilaterally, from the planum posteriorly to the posterior wall of the frontal sinus anteriorly.

  • The dura is resected and a complete anterior fossa resection is performed. This includes bilaterally transecting the olfactory tracts.

  • A multi-layered dural reconstruction is performed, which includes an intradural inlay and overlay Alloderm graft, abdominal fat, and sealant. The multi-layered reconstruction is supported intranasally, with placement of packing under direct visualization and the balloon of a Foley catheter.

The goal of surgery is to achieve complete tumor resection with negative margins. The number of studies reporting success with the endoscopic approach without compromising effectiveness in the short term is increasing. In a review of treatment in 533 patients with ENB, multivariate regression showed a trend toward higher 5-year overall survival with endoscopic versus open surgery, regardless of Kadish stage, although the difference did not reach clinical significance.[42]

The decision between endoscopic versus craniofacial resection should be evaluated on an individual case basis. Considerations should include the extent of tumor progression as well as the histopathologic and morphologic characteristics of the tumor.

Neck metastasis

Neck metastasis at presentation occurs in 5–7% of patients. When neck disease is diagnosed at the initial presentation, it should be treated surgically.[43]

In their literature review, Beitler et al found an incidence of delayed neck metastasis of 19%, but half of these patients also presented with local recurrence.[44] Salvage treatment was successful in 70% of these patients. Contrary to the conclusion of Beitler et al, the authors do not consider that a 10% rate of delayed neck recurrence represents justification for elective neck dissection in all cases of ENB.


Usually, patients with head and neck tumors are treated in academic centers with broad expertise with prospective treatment programs outlined in the multidisciplinary tumor board. Head and neck tumor boards usually include a head and neck surgeon and radiation and medical oncologists. Speech language pathologists, psychosocial oncologists, nutritional and social work support, and dental consultations are available. Maxillofacial and prosthetic consultants are incorporated as needed. The treatment protocol is decided in common, and each specialist performs his or her own specific task as described above.

  • A craniofacial team, in which neurosurgeons form an essential part, usually manages an esthesioneuroblastoma (ENB) surgically. Most of the important complications after surgery concern the brain and calvarium; thus, close neurosurgical follow-up is necessary.

  • For ENB, a preoperative ophthalmology evaluation is mandatory because the optic nerves are at risk during either radical surgery or radiation therapy. In addition, ophthalmologists can be helpful if partial intraorbital resection is contemplated. Dacryocystorhinostomy usually is performed during surgery, and ophthalmologists can provide help in this procedure and/or the postoperative evaluation of the lacrimal system.

  • If an associated palate resection is contemplated, the upper dental prosthesis should be made before surgery and placed at the end of the procedure. This usually achieves a separation of the oral cavity from the nasal cavity and allows adequate oral nutrition. Adjustments of this prosthesis are required after ablation of the nasal packing and in response to tissue scarring and/or retraction that take place within 6 months after completion of treatment.


No specific postoperative dietary restrictions are required for patients with esthesioneuroblastoma (ENB).

  • Following major surgery, patients tolerate only light meals during the first postoperative days.

  • Patients with a history of constipation should be given stool softeners for the first postoperative week to prevent undue straining and allow the skull base repair to heal.


See the list below:

  • Some surgeons routinely place a lumbar drain to decrease pressure on the dural repair. The authors tend to restrict CSF decompression to cases with significant dural sacrifice and replacement and/or when the base of skull repair is deemed fragile. As long as the drain remains in place, patients require strict bed rest.

  • Otherwise, patients usually are out of bed on the first postoperative day.

  • Patients should be advised to not blow their noses for several days and to open their mouth during sneezing and coughing to avoid the creation of pneumocephalus.



Medication Summary

Chemotherapy as a treatment modality has historically been reserved for unresectable tumors, recurrence, or metastatic disease. Most reports suggest that chemotherapy is reserved as part of multimodality treatments. Palliative chemotherapy can be beneficial for relieving pain and obstruction or debulking tumors when surgery is not an option (either high risk or patient refusal of surgery).



Further Outpatient Care

Nasal irrigation with sterile isotonic sodium chloride solution begins within a few days after packing removal. Removal of nasal crusting should be performed regularly during initial postoperative visits. This problem is aggravated during radiotherapy but decreases in most patients after 1-2 years. It is a lifelong burden for which no good treatment or prevention is available.

Craniotomy sutures are removed 7-10 days after surgery. If a facial incision has been used, sutures are removed after 5 days

Further Inpatient Care

In the first 48 hours following craniofacial resection, regular neurosurgical evaluation is required. ICU monitoring for at least 24 hours also is necessary. Duration of the lumbar drainage is controversial, varying from intraoperative only to as long as 7 days.

Aspiration of the nasal trumpets should be performed several times a day. Nasal packing is left in place for 5-7 days. Removal of large nasal packing is uncomfortable, and some pain medication could be administered before the procedure.

Inpatient & Outpatient Medications

Antibiotic prophylaxis is usually started before surgery for esthesioneuroblastoma and includes coverage for gram-positive bacteria. Because good intracerebral penetration is preferred, ceftriaxone often is a good choice. Postoperatively, the authors continue antibiotics while the nasal packing remains in place.


Craniofacial resection for esthesioneuroblastoma (ENB) has been associated with a complication rate of 10-15%. Higher rates of complications (up to 30%) have been observed in cases of revision or salvage surgery or surgery following radiation or chemoradiation therapy.

The most frequent problems are infections, including abscess surrounding the bone flap; meningitis; and, less often, subdural or epidural abscess.

Meningitis sometimes is related to the presence of a cerebrospinal fluid leak, because the closure of the anterior skull base is not always watertight.

Pneumocephalus has been another difficult problem to prevent. Although self-limiting in most cases, pneumocephalus can result in brain compression and requires needle aspiration through the trephine bony holes.

Blindness, secondary to optic nerve injury, and death either from intracerebral bleeding or internal carotid injury have become exceptional.

Inform patients that olfactory function is likely to be altered or absent after surgery. In addition, nasal crusting is a long-lasting problem that requires daily nasal irrigation for several years.

Delayed complications include necrosis of the frontal bone flap, lacrimal drainage obstruction, and frontal sinus mucocele.

Radiation-related complications also are rare and include lacrimal duct blockage and tearing, postradiation cataract, osteoradionecrosis of the frontal bone flap, radiation retinopathy, and blindness.


See the list below:

  • Treatment results before the availability and use of modern diagnostic techniques were flawed, probably by the inclusion of cases of sinonasal undifferentiated carcinoma and sinonasal neuroendocrine carcinoma, 2 aggressive diseases associated with poor survival. The importance of correctly differentiating these cancers is highlighted in a recent report by Rosenthal et al.[45] For a discussion of posttreatment prognosis, see Kane et al.[10]

  • In recent series, the 5-year patient survival rates have varied from 50-80%, with the majority of large studies indicating patient survival rates of higher than 70%. In the 2001 meta-analysis by Dulguerov et al, the average 5-year survival was 45 ± 22% (range, 0-86%).[24]

  • Whether the Kadish classification system has a definitive prognostic value remains unknown, but the available survival data for stages A, B, and C are 72%, 59%, and 47%, respectively. According to the Dulguerov staging system, the survival rates were 81% for T1, 93% for T2, 59% for T3, and 48% for T4.

Prognostic survival factors that emerged in the meta-analysis by Dulguerov et al include lower Hyams histopathologic grade (56% for grades I-II vs. 25% for grades III-IV) and absence of neck lymph node metastasis (64% for N0 vs. 29% for N+).[24]

Other possible but unconfirmed prognostic factors include a low proliferative index, the completeness of the surgical resection, and tumor shrinkage after induction chemotherapy.

Survival data categorized according to treatment modality favored regimens that include surgery.

The most frequent recurrence is local, with rates from 20-40% (29% in the Dulguerov et al meta-analysis). Craniofacial resection followed by radiation seems to result in fewer recurrences, a rate of approximately 10%. Salvage after local recurrence is possible in one third to one half of cases.

Regional recurrence, while disease at the primary site remains under control, occurs in 15% of cases and is salvageable by further treatment in 25-50% of cases. Distant metastasis with locoregional control occurs infrequently (8%) and carries a dismal prognosis.

Recurrence may occur years after the completion of treatment, often more than 10 years; therefore, prolonged follow-up is required, although the optimal frequency of medical visits and the necessity of radiologic studies have not been precisely determined.